MTC-20172
'S' Interface Circuit
for ISDN (SIC)
Data Sheet &
Reference Manual
Rev. 1.1 February 1997
Application Specific Standard Products
Analog
transmitter
s_transmitter
DPLL
s_receiver
FL detection
M control
buffer
activity
detector
7680 kHz
oscillator
asynchronous
power up/down
V*/GCI
DIN
DOUT
DFR
DCLK
status
controller
Analog
receiver
MUX
C/I
S, Q
B, D
B, D
SX
P
S, Q
SX
N
SR
P
SR
N
XTI
XTLO
B, D
B, D
CHP boundary
Block Diagram
Features
Single chip 4 wire S0-interface
for ISDN
Basic access at 144 kbits/s,
with 2B+D
Complying with CCITT I.430
Applicable in all ISDN
So-interface Configurations :
- NT : Network Termination
- TE : Terminal Equipment
- LTS : Line Termination
Subscriber
- LTT : Line Termination Trunk
Switching of Test-loops
S-bus drivers with high-
impedance when not powered
Balanced S-bus receivers
Line-length up to 1.2 km in
point-to-point configuration
Handles V*, IOM1™, IOM2 ™
and GCI digital interfaces
Supports Multiframing
Includes Maintenance channel
Absorption of clock wander in
LTT mode
Operating power < 50 mW
Stand-by power < 3 mW
Single 5V supply
™ IOM is a trademark of Siemens
Table 6.4.a : MTC-20172 SIC C/I : NT overview
NT Downstr Upstr. Downstr Upstr.
Command Indicat. Command Indicat
0000 DR TIM 1000 ARd ARu
0001 -& * RES (lsl)*&- 1001 - -
0010 ssz=TM1 - 1010 ARL -
0011 -& * TM2 - 1001 - -
0100 RSYd RSYu 1100 AId AIu
0101 - - ++ 1101 - -
0110 - ei * &- 1110 AIL -
0111 - - 1111 did=DC DIu
6.5.8 Command and Indications for NT Applications.
++ MAIC is NOT implemented.
* Marks functional differences
(4 in total).
& Marks functional differences which
are merged for both devices.
6.5.8.1 Commands (Downstream) in NT Mode
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table 6.4.b : MTC-20172 SIC commands (DS) NT
0000 DR # Deactivate Forces MTC-20172 SIC to deactiv. the S-bus (=INFO0)
Request followed by DIu and did=DC
0001 *RES # RESET Forces MTC-20172 SIC to soft reset, extended mode only,
& MTC-20172 SIC accepts it in basic mode (merged)
0010 ssz # TEST-MODE 1 Forces MTC-20172 SIC to test-mode 1, sending
= TM1 single zeros
0011 *TM2 # TEST-MODE 2 Forces MTC-20172 SIC to test-mode 2, extended mode
& only, sending continuous zeros, command is
extended to the basic mode of the MTC-20172 SIC
0100 RSYd Resynchon- The U-interface is not synchronous, MTC-20172 SIC
izing down sends INFO2 {or SCZ}, see remark 1 below
1000 ARd Activation MTC-20172 SIC forced to INFO2 transmission,
Request down receiver indicates the S-bus reaction
1010 ARL Activat. req INFO2 transmission on the S-bus
with S-loop test loop2 switched (transparent loop)
1100 AId Activation INFO4 transmission, normally only after
Indication AIu indication is received
1110 AIL Activ. Indic. INFO4 transmission
with S-loop test loop2 switched (transparent loop)
1111 did= Deactivate Deactivation confirmation, entering the
DC Confirmation power down state, INFO0 sent, critical
timing to halt the clocks, see 6.2.4
* Marks functional difference;
& Marks differences that are merged.
# Unconditional commands, which
force an unambiguous state.
Remark 1: When the U-interface is
resynchronizing, the basic mode sends
Continuous Zeros, the extended mode
sends INFO2. MTC-20172 SIC will
send INFO2.
Remark 2: During loops, the MTC-
20172 SIC simply ignores the incoming
INFO3 from the S-bus. The receiver
synchronizes on looped INFO2/4.
ERRATA
Page 56, Table 6.4.b, shows incorrect command codes for the Ald and AIL states.
The correct table is given here.
1. General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Interface and Operation Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1 The Digital Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 The So-INTERFACE - Functional overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3 The MTC-20172 SIC Operation Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Test Modes Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Pin and Package Data
3.1 Package and Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Pin Allocation and Short Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3 Input/Output Types in Function of the Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
3.4 Values and Usage of the Pull-Up Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
3.5 Device Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4. Functional Description
4.1 General Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.2 Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3 Improved Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.4 Overview of the Use of MTC-20172 SIC in the ISDN System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.5 General Description of the S-BUS Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.6 The GCI Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.6.1 The Physical Organization of the GCI Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.6.2 General Content of the GCI Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.6.3 Power-down on GCI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.7 GCI Clock-Synchronization in the ISDN Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.8 Clock Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.9 Power Saving / Deactivation of MTC-20172 SIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.10 MTC-20172 SIC Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.10.1 MTC-20172 SIC Activation in NT Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.10.2 MTC-20172 SIC Activation in TE Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.10.3 MTC-20172 SIC Activation in LT/S and LT/T Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.10.4 Crystal Oscillator Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.11 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.12 Functional Explanation of the Special Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5. Detailed Operational Description of the S-Bus Interface
5.1 General Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.1.1 Transmission Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.1.2 Frame Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.1.3 AMI S-bus Coding (general in RX and TX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.1.4 Balance Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.1.5 AMI Violations For Frame Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.1.6 Frame Synchronization; Distance Rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.1.7 Frame Synchronization; Multiframing Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.1.8 Synchronization Principles, with Adaptive Bit-timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
III
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table of Contents
5.1.9 Synchronization Principles, Fixed Bus Timing at NT/LT-S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.1.10 Pulse Polarity in the S-bus Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.1.11 Transmitted Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.2 S -BUS Transmitter Analog Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.2.1 Polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.2.2 MTC-20172 SIC Drivers, External Transformer and Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.2.3 Ternary Drivers : High-Ohmic State when not powered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.2.4 Ternary Driver : Compatibility and Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.2.5 S-bus Transmitter Timing and Framing; Jitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.3 S -BUS Receiver: Analog Parts and Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.3.1 Transformer and other External Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.3.2 Ternary S-bus Receiver Polarity and Balanced Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.3.3 Ternary Receivers : Impedance while not powered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.3.4 Activity Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.3.5 Sensitivity/AGC: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.3.6 MTC-20172 SIC RX Signal Dynamics and Detection at TE/LT-T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.3.7 MTC-20172 SIC RX Signal Dynamics at NT/LT-S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.3.8 MTC-20172 SIC RX Detection Levels at NT/LT-S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.3.9 Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.3.10 RX Frame Sync and Bit-sampling in NT/LT-S Short Bus Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.3.11 Frame Synchronization Details In Adaptive Timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.3.12 RX Bit-Synchronization in TE/LT-T and NT/LT-S Adaptive Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.4 Timing Relation Between RX and TX on the S-BUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.4.1 S-bus Transmitter Versus Receiver Delay in TE/LT-T Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.4.2 S-bus Receiver Versus Transmitter Delay in NT/LT-S Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.4.3 Delay Trimming via XTR4 Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.4.4 More Delay Trimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.5 Frame Relation Between GCI and S-INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.5.1 S-bus Transmitter Bit and Frame Clock NT/LT-S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.5.2 S-bus Transmitter Clock and Frame in TE Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.5.3 Transmitter Clock and Frame in LT-T Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.6 E-Channel Generation in NT/LT-S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.6.1 E-channel Generation in NT In STAR Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.6.2 E-channel Generation in LT-S For HDLC Pooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.6.3 E-channel Generation : Operational . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.7 D-Channel Access in TE/LT-T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.7.1 D-channel Access Working Principles for the MTC-20172 SIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
5.7.2 The D-channel Access Controller (D-AC) Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
5.7.3 READY Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.7.4 Anticipation and LAPD Fairness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.7.5 RDY Pin and Bit Operation in Basic Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.7.6 Timing and Operation in Extended . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.7.7 Illegal Messages from the HDLC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.7.8 E-channel to External-HDLC Device at TE Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.8 D-Channel Access in NT/LT-S : TIC Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.9 Multiframing; S and Q Channel Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.9.1 Compatibility With Older MIETEC MTC-2072 SIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.9.2 Multiframing Enabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.9.3 Functional Behaviour at The NT/LT-S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.9.4 Functional Behaviour at TE/LT-T Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
5.9.5 Automatic S and Q Bit Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
5.9.6 Multiframing and S-bus Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
5.10 BER PIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
IV
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
6. The GCI Interface
6.1 The GCI Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.1.1 General Content of the GCI Bus for the MTC-20172 SIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.2 The Physical Organization of the GCI BUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.2.1 Clock and Frame Signals (see Figure 9.2.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.2.2 Channel Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.2.3 DATA Pin Tristate or Open Drain Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.2.4 Power-down and Power-up on the GCI Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.3 The B-Channels on the GCI Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
6.4 The D-Channels on the GCI Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
6.5 The Command/Indication (C/I) Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
6.5.1 General Information on the C/I State Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
6.5.2 State Diagram for the NT Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.5.3 State Diagram for the LT-S Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.5.4 State Diagram for the TE/LT-T Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
6.5.5 The Commands and Indications, Basic Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
6.5.6 Commands and Indications Extended Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
6.5.7 C/I Equivalence Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.5.8 Command and Indications For NT Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.5.9 Commands and Indications LT-S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
6.5.10 Commands and Indications TE/LT-T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
6.6 M-Channel + MX + MR : Physical Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
6.6.1 M-channel Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
6.6.2 M-channel Format, Bit and Byte Numbering Convention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
6.6.3 Byte Transfer Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
6.6.4 Comments on the MTC-20172 SIC M-transceiver State Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
7. M-Channel Messages and Registers
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
7.2 M-Channel Receiver and Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
7.3 General Content of M-Channel Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
7.4 M-Channel, Basic Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
7.5 S and Q Channel M-Channel Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
7.5.1 S/Q M-channel Messages, MTC-20172 SIC in NT/LT-S with Multiframing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
7.5.2 S/Q M-channel Messages, MTC-20172 SIC in TE/LT-T with Multiframing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
7.5.3 S/Q M-channel Messages, MTC-20172 SIC Multiframing Disabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
7.6 Internal Register M-Channel Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
7.6.1 Write Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
7.6.2 READ Operation and CONTENT Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
7.7 Detailed Bitmap of the Internal Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
7.7.1 Identification Register; READ Only; Address 0h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
7.7.2 Version Number Register; READ Only; Address 1h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
7.7.3 Configuration Register; WRITE and READ; Address 2h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
7.7.4 Output Register; WRITE and READ; Address 3h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
7.7.5 IN1 and IN2 Registers; READ Only; Address 4h and 5h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
7.7.6 Performance Register; READ Only; Address 6h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
7.8 M-Channel Operation Messages Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
7.9 Reset of the M-Channel Transceiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
VI
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
8. Loops, Test Modes, System Tests
8.1 Wafer Test of the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
8.2 Packaged Device Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
8.3 Equipment Tests, ISDN LOOP Tests, Acceptance Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
8.3.1 Test of the device on the assembled DSP board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
8.3.2 ISDN Loops and Other Tests of the Complete Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
8.4 System Tests, for Characterization of all Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.4.1 PLL and DPLLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.4.2 State Machines of the C/I Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.4.3 M-channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.4.4 D-channel Access Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.4.5 Echo Channel and Echo Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.4.6 S-bus Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.4.7 S-bus Input to Output (TE/LT-T) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.4.8 Power-down in NT and TE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.4.9 Power-up in NT and TE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
9. Electrical, Physical and Environmental Specifications
9.1 Limiting Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
9.2 Transient Energy Capabilities : ESD and LATCH-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
9.3 Thermal Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
9.4 Recommended Electrical Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
9.5 Static Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
9.5.1 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
9.5.2 Static Characteristics of Digital Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
9.5.3 Static Characteristics of Digital Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
9.5.4 Static Characteristics of Analog S-bus Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
9.5.5 Static Characteristics of Analog S-bus Outputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
9.6 Dynamic Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
9.6.1 Master Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
9.6.2 DCL Output Clock (TE) and Other Derived Clock Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
9.6.3 Serial GCI Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
9.6.4 RDY Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
9.6.5 ECHO Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
9.6.6 RSTB Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
9.6.7 DE/CEB Bus Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
9.6.8 BER Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
9.6.9 TM1-, TM2-, SCZ-, SSZ- Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
9.6.10 The AUX Pins used as General Purpose I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
10. Quality and Reliability Specification
10.1 Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
10.1.1 Product Acceptance Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
10.1.2 Lot-by-lot Acceptance Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
10.1.3 Assembly Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
10.1.4 Delivery Lot Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
10.1.5 Quality System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
10.2 Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
10.2.1 The Intrinsic Failure Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
10.2.2 External Stress Immunity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
10.2.3 The Useful Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
11. Related Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
12. Application Note : ETS-TM3 Qualification
12.1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
12.2 External Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
12.3 ETS-TM3 Configuration Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
12.3.1 Network Terminations(NT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
12.3.2 ETS-TM3 Terminal Equipments (TE,LTT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
12.4 Qualification Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
12.4.1 Transformer VAC ZKB505/105 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
13. Application Note : Network Terminator
13.1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
13.2 NT Mode with MTC20171 4B3T UIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
13.2.1 Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
13.2.2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
13.3 Requirement for the Input and Output Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
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AGC . . . . . . . . . . . . . . . . . . . . . Automatic Gain Control
AMI . . . . . . . . . . . . . . . . . . . . . Alternating mark inversion
CLCC . . . . . . . . . . . . . . . . . . . . Ceramic Leaded Chip Carrier
C/I . . . . . . . . . . . . . . . . . . . . . . Control/Indication
CMOS . . . . . . . . . . . . . . . . . . . Complementary MOS (Metal Oxide Silicon) technology
D-AC . . . . . . . . . . . . . . . . . . . . D-channel Access Controller
DIL . . . . . . . . . . . . . . . . . . . . . . Dual In-Line package
DPLL . . . . . . . . . . . . . . . . . . . . . Digital Phase Locked Loop
ESD . . . . . . . . . . . . . . . . . . . . . . Electro Static Discharge
ILC . . . . . . . . . . . . . . . . . . . . . . . ISDN - link - controller
IOM . . . . . . . . . . . . . . . . . . . . . ISDN Oriented Modular (interface), Siemens Trademark
ISDN . . . . . . . . . . . . . . . . . . . . Integrated Services Digital Network
GCI . . . . . . . . . . . . . . . . . . . . . . General Circuit Interface
HDLC . . . . . . . . . . . . . . . . . . . . High-level Digital Link Control, see also LAPD
LAPD . . . . . . . . . . . . . . . . . . . . Link Access Protocol for D-channel, CCITT Q.921
LCL . . . . . . . . . . . . . . . . . . . . . . Longitudinal Conversion Loss
LSB . . . . . . . . . . . . . . . . . . . . . . Least Significant Bit
LT . . . . . . . . . . . . . . . . . . . . . . . . Line Termination, see Figure 4.1
LT-S . . . . . . . . . . . . . . . . . . . . . Line Termination at the S interface (S-bus toward TE)
LT-T . . . . . . . . . . . . . . . . . . . . . . Line Termination at the T interface (S-bus toward NT)
MSB . . . . . . . . . . . . . . . . . . . . . Most Significant Bit
NT . . . . . . . . . . . . . . . . . . . . . . . Network Termination, see Figure 4.1
NT1 . . . . . . . . . . . . . . . . . . . . . Network Termination, see Figure 4.1
NT2 . . . . . . . . . . . . . . . . . . . . . Intelligent Network Termination, see Figure 4.1
PABX . . . . . . . . . . . . . . . . . . . . Private Automatic Branch Exchange
PCBA . . . . . . . . . . . . . . . . . . . . Printed Circuit Board Assembly
PLCC . . . . . . . . . . . . . . . . . . . . Plastic Leaded Chip Carrier
PLL . . . . . . . . . . . . . . . . . . . . . . Phase Locked Loop
RAM . . . . . . . . . . . . . . . . . . . . . Random Access Memory
RX . . . . . . . . . . . . . . . . . . . . . . . Receive
SDL . . . . . . . . . . . . . . . . . . . . . . System description language
SIC . . . . . . . . . . . . . . . . . . . . . . S-interface-circuit
SLMD . . . . . . . . . . . . . . . . . . . . Subscriber line module digital
SIC . . . . . . . . . . . . . . . . . . . . . . S-interface Integrated Circuit
TE . . . . . . . . . . . . . . . . . . . . . . . Terminal equipment, see Figure 4.1
TX . . . . . . . . . . . . . . . . . . . . . . . Transmit
UIC . . . . . . . . . . . . . . . . . . . . . . U-Interface Circuit
VLSI . . . . . . . . . . . . . . . . . . . . . Very Large Scale Integration
X-tal . . . . . . . . . . . . . . . . . . . . . crystal
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List of Abbreviations
Fig. 1. Typical Application
Fig. 2.1 Timing in Normal mode
Fig. 2.2 Timing in V* Inverted mode
Fig. 2.3 Timing in V* Inverted Multiplexed mode
Fig. 2.4 Format of a V* GCI channel
Fig. 2.5 S0 Frame Format
Fig. 2.6 Point-to-point configuration
Fig. 2.7 Point-to-multipoint configuration
Fig. 2.8 Block Diagram
Fig. 2.9 Test loops
Fig. 2.10a Pinout, 22PDIL version
Fig. 2.10b Pinout, 28PLCC version
Fig. 3.1 22 pin DIP package and dimensions.
Fig. 3.2 28 pin PLCC square package and dimensions.
Fig. 3.3 22 pin DIP, signal names.
Fig. 3.4 28 pin PLCC, signal names.
Fig. 4.1 MTC-20172 SIC Applications
Fig. 4.2 Frame Structure GCI
Fig. 5.1 S Frame Structure
Fig. 5.2 S Coding with AMI
Fig. 5.3 Pulse Mask 50
Fig. 5.4 Pulse Mask 400
Fig. 5.5 GCI S-bus Phase Relation TE Mode, RDY & ECHO pin
Fig. 5.6 GCI S-bus Phase Relation NT/LT-S Mode, DE/CEB timing
Fig. 5.7 State Diagram of D-Channel Access Procedure
Fig. 6.1 Relation of clock, frame and data on the GCI bus
Fig. 6.1a Deactivation of the GCI interface
Fig. 6.2 SDL Diagram NT
Fig. 6.3 SDL Diagram LT-S
Fig. 6.4 SDL Diagram TE, LT-T
Fig. 6.5 Explanation of Notation of the SDL Diagrams
Fig. 6.6 SDL Diagram TE/LT-T, Unconditional states, Basic Mode
Fig. 6.7 Activation Sequence Outgoing Call
Fig. 6.8 Activation Sequence Incoming Call
Fig. 6.9 Deactivation Sequence
Fig. 6.10 SDL Diagram TE/LT-T, Unconditional states, Extended Mode
Fig. 6.11 SDL Diagram of the M-channel Receiver
Fig. 6.12 SDL Diagram of the M-channel Transmitter
Fig. 6.13 Examples of Received M-channel Messages
Fig. 6.14 Examples of Transmitted M-channel Messages
Fig. 9.1 Pulse Form of the 7.68 MHz Clock
Fig. 9.2 GCI Timing Parameters in TE
Fig. 9.3 GCI Timing Parameters in NT, LT-S and LT-T Mode
Fig. 12.1 Application circuitry for MTC20172 SIC
Fig. 12.2 Output pulse template for 50
Fig. 12.3 Output pulse template for 400
Fig. 12.4 Output impedance State_F1
Fig. 12.5 Output impedance State_F3
Fig. 12.6 Intput impedance State_F1
Fig. 12.7 Intput impedance State_F3
Fig. 13.1 MTC20172 SIC in NT mode with MTC2071 UIC
Fig. 13.2 Schematic of MTC20172 input and output Stage
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MTC-20172
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Rev. 1.1 February 1997
List of Figures
Table 2.1 : Possible Mode combinations
Table 3.1 : Pin list and description, 22 and 28 pin package
Table 3.2 : Input/Output types in function of the modes
Table 4.1 .a : SBC 2080 compatible modes of operation with the MTC-20172 SIC
Table 4.1 .b : SBCX 2081 compatible modes of operation with the MTC-20172 SIC
Table 4.2 : Mode-selection pins in MTC-20172 SIC
Table 5.1 : Multiframing Sequence
Table 6.1 : Basic Mode Commands and Indications
Table 6.2 : Extended Mode Commands and Indications
Table 6.3 : Equivalent table for Basic Mode versus Extended Mode
Table 6.4 .a : MTC-20172 SIC Commands/Indications NT: overview
Table 6.4 .b : MTC-20172 SIC Commands (Downstream) in NT mode
Table 6.4 .c : MTC-20172 SIC Indications (Upstream) in NT mode
Table 6.5 .a : MTC-20172 SIC Commands/Indications LT-S: overview
Table 6.5 .b : MTC-20172 SIC Commands (Downstream) in LT-S mode
Table 6.5 .c : MTC-20172 SIC Indications (Upstream) in LT-S mode
Table 6.6 .a : MTC-20172 SIC Commands/Indications TE/LT-T: overview
Table 6.6 .b : MTC-20172 SIC Commands (Upstream) in TE/LT-T mode
Table 6.6 .c : MTC-20172 SIC COMMON INDICATIONS (Downstream) in TE/LT-T mode
Table 6.6 .d : MTC-20172 SIC INDICATIONS (Downstr.) Basic Mode only, TE/LT-T mode
Table 6.6 .e : MTC-20172 SIC INDICATIONS (Downstr.) Extended Mode only, TE/LT-T mode
Table 7.1 : Register Bitmap of MTC-20172 SIC
Table 7.2 : M-channel Message Overview
Table 9.1 : Static Characteristics of the Power Supply.
Table 9.2 : Static Electrical Characteristics, Digital Inputs.
Table 9.3 : Static Electrical Characteristics, pull-up resistors
Table 9.4 : Static Electrical Characteristics, outputs
Table 9.5 : Static Characteristics of the S-bus Inputs
Table 9.6 : Static Characteristics of the S-bus Outputs
Table 9.7 : Dynamic Characteristics of the Master Clock
Table 9.8 : Dynamic Characteristics of Derived Clock Signals
Table 9.9 : Characteristics of GCI Signals, Master modes
Table 9.10 : Characteristics of GCI Frame, Slave modes
Table 9.11 : Characteristics of GCI Data, Slave modes
Table 10.1 : Acceptance criteria
Table 10.2 : Assembly monitor
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
List of Tables
1. General Description
SUBSCRIBER PREMISES
U I C
Public
Exchange
U I C
S I C
Network
Termination
Module
(NT)
I
C
S
L
C
I
I
C
S
L
C
I
PABX
PABX
LTS
U I C
S I C
Network
Termination
Module
(NT)
U I C
Public
Exchange
S I C
I L C
Terminal
Equipment
(TE)
PUBLIC EXCHANGE
max 8
max 8
S I C
I L C
Terminal
Equipment
(TE)
LTT
The MTC-20172 is an enhanced
version of the MTC-2072 SIC. In
addition to the basic line interface
functions, the MTC-20172 offers
digital interfaces compatible with most
commonly used standards (V*,
IOM1™, IOM2™, GCI), as well as
extended monitor channel functions
and multi-framing. The use of state-of-
the-art process technologies and
restructuring of the analog functions
results in greatly enhanced analog
performance.
The S0-interface circuit (SIC) enables
full duplex digital data transmission
(2B+1D) over the So-interface. The
SIC can be used as a ‘Network
Termination’ (NT), providing
transparent data transmission from the
digital interface to the So-interface
and vice versa. As a ‘terminal
equipment’ device (TE), the SIC is
connected to a "layer 2" device (e.g.
ISDN Link Controller; MTC-2074 ILC)
which provides HDLC data formatting
for the D channel, etc... To connect an
ISDN PABX unit to the public network,
an SIC can be used as a ‘Line
Termination Trunk side’-device (LTT). In
addition, a ‘Line Termination
Subscriber side’ (LTS) mode is
available (fig.1), which is similar to
NT but offers simpler
activate/deactivate procedures.
A digital serial interface provides a
link between the MTC-20172 SIC
and, for example, the MTC-2071
4B3T U-Interface, the MTC-2074 ILC
(HDLC and DMA controller) or other
communication devices. The digital
serial interface supports V*, IOM1™ ,
IOM2™ and GCI, so is compatible
with many other integrated circuits for
ISDN communications. The SIC
contains all necessary functions for
direct connection to the S0-interface,
and specifically the critical analog
transmitter and receiver stages.
(See also section 4).
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Fig. 1 : Typical Application
Only 1 channel is available.
This mode is applicable in TE mode.
V* Inverted Multiplexed Mode
(fig. 2.3)
Inverted frame and data clock.
DCLK = 4096 kHz (256 bits/frame)
DFR goes low for 1 clock cycle at the
end of position 251.
8 channels are available.
This mode is applicable in LTT and LTS
modes.
Remark: In LTS and LTT applications,
there is automatic recognition of
inverted multiplexed and normal
modes.
A channel of 32 bits is divided into 4
bytes (fig. 2.4):
1st byte B1:
First transparent data channel of 64
kBits/s.
2. Interface and Operation Overview
2.1 The Digital Interface
Each ISDN configuration (NT, TE, LTS,
LTT) is supported in either V* or in
GCI standards. The serial interface is
made up of frames of 125 µs. Each
frame can have from 32 to 512 bit
positions and is divided into channels
of 32 bits. Each bit takes 2 cycles of
the data clock DCLK (with a frequency
from 512 kHz to 8192 kHz). The start
of a 125 µs frame is synchronized
with a DFR (Data FRame) signal of 8
kHz. In TE modes, the SIC is master of
the digital interface, in NT, LTS and
LTT modes, the SIC is a slave.
Depending on the mode selected,
several frame formats are possible :
Normal Mode (fig. 2.1)
DCLK can go from 512 kHz to 8192
kHz with intervals of 16 kHz (32 to
512 bits/frame).
The rising edge of DFR marks the start
of the frame and should be high for at
least 2 DCLK periods.
Depending on the DCLK frequency, a
maximum of 8 channels are available.
The bits of the higher channels are
unused.
This mode is applicable in all
configurations.
V* Inverted Mode (fig. 2.2)
Inverted frame and data clock.
DCLK = 512 kHz (32 bits/frame)
DFR goes low for 1 clock cycle at the
end of position 27.
2
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Fig. 2.1 : Timing in Normal Mode
Signal
DFR: 8 KHz
DIN: 256 - 4096 KBit/s
DOUT: 256 - 4096 KBit/s
Bit no.
Channel no.
0
1
2
3
4
5
6
7
0
8
9
10
NORMAL MODE
Fig. 2.2 : Timing in V* Inverted Mode
Signal
DCLK: 4096 KHz
DFR: 8 KHz (PULSE)
DIN: 2048 KBit/s
DOUT: 2048 KBit/s
Bit no.
30
31
0
1
2
3
4
5
29
28
27
26
6
7
8
INVERTED MODE
Fig. 2.3 : Timing in V* Inverted Multiplex Mode
Signal
DCLK: 4096 KHz
DFR: 8 KHz (PULSE)
DIN: 2048 KBit/s
DOUT: 2048 KBit/s
Bit no.
30
31
0
1
2
3
4
5
29
28
27
26
6
7
8
INVERTED MULTIPLEXED MODE
Channel no.
7
0
3
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
MR
MX
C/I
D1D2
B1
IN
B2*
B2
B1*
User Data
Monitor Channel
C/I channel
MR
MX
C/I
D1D2
B1
OUT
B2*
B2
M1 …… M8
32 Bit
Fig. 2.4 : Format of a V* CGI Channel
The possible combinations of ISDN configurations, frame format and
activation/deactivation procedures are shown in TABLE 2.1.
(†) Compatible with the MTC-2072 SIC.
Table 2.1 : Possible Mode combinations
ISDN configuration Frame format DCLK frequency Available Activation/
(kHz) channel Deactivation
according to
TE(†) Inverted 512 1 V*
TE(†) Normal 512 1 V*
LTS/LTT(†) Inverted multiplexed 4096 1-8 V*
LTS/LTT Normal 512-8192 1-8 V*
LTS/LTT(†) Normal 512-8192 1 V*
NT(†) Normal 512-8192 1 V*
TE Normal 1536 1 GCI
LTS/LTT Normal 512-8192 1-8 GCI
NT Normal 512-8192 1 GCI
2nd byte B2:
Second transparent data channel of
64 kBits/s.
3rd byte B2*:
Monitor channel, with (in TE and LTT)
the D-channel status in the 5th bit
position.
4th byte B1*:
D1, D2: Two transparent D-channel
bits at 16 kBits/s.
C/I: Four Command/Indication
channel bits. These are used for
activation or deactivation and
test modes.
The interpretation of the received
command codes and the transmitted
Indications follow the V* or the GCI
C/I code tables.
MR, MX: Two handshaking bits to
control the monitor channel access.
4
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
N : = FA
B1 : BIT OF CHANNEL B1
B2 : BIT OF CHANNEL B2
A : ACTIVATION BIT
S : S-BIT
M : MULTIFRAMING BIT
F : FRAMING BIT
L : DC BALANCING BIT
D : D-CHANNEL BIT
E : D-CHANNEL ECHO-BIT
FA : AUXILIARY FRAMING BIT
D
L.
F
L.
B1
L.
D
L.
FA
L
B2
L.
D
L.
L.
D
L.
L.
D
L.
F
L.
D
L.
F
L.
B1
E
D
A
FA
N
B2
E
D
M
B1
E
D
S
B2
E
D
L.
F
L.
2 BITS OFFSET
NT to TE
TE to NT
B1
B2
Fig. 2.5 : So-Frame Format
2.2The So-Interface
- Functional overview
For transmission of data over the
subscriber premises, the SIC provides
the S0-interface. This interface enables
full duplex transmission of data (2B + 1
D-channel) over 4 wires at a nominal
data rate of 192 kBits/s. An Alternating
Mark Invert (AMI) code is used for the
line transmission. The transmission of
data over the S0-interface consists of
frames of 250 µs. Each frame is 48 bits
wide, and contains 4 data bytes (2 B1,
2 B2) and 4 D-bits.
The frame structures are shown in
fig.2.5.
A frame start is marked using a first
code violation (no mark inversion).
To allow secure synchronization of the
receiver, a second code violation is
generated before the 14th bit of the
frame. To guarantee this second
violation, an auxiliary framing bit pair
FA and N (from NT to TE) or the
framing bit FA with associated balance
bit (from TE to NT) are introduced.
The first bit of the transmitted frame from
TE to NT is delayed for 2 bit periods
with respect to the frame received from
the NT. Furthermore, an echo bit (E-bit)
for the D-channel and an activation bit
(A-bit) are provided, where DC-
balancing is done by means of the L-
bits.
The SIC supports multi-framing
according to CCITT I.430
recommendations - the capability of
transmitting an S-channel from NT to TE
and a Q-channel from TE to NT of 800
baud is provided for. The S and Q data
can be accessed via the monitor
channel.
5
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
The SIC can be used in a point-to-point
and in a point to multipoint
configuration (including extended
passive bus). In the first configuration,
the length of the cable is limited to
aprox. 1.2 km (see fig.2.6).
In the bus configuration (point to
multipoint), up to 8 terminals may be
connected to the S0-interface (fig.2.7).
The terminals must be connected in a
range of 150 m. For the extended
passive bus, the terminals must be
clustered within a 25m range with a
maximum cable length of about 1 km.
To avoid bus mismatching when
multiple TEs are connected, the driver
stages present a high impedance
when they are not powered.
Controlled access to the shared data
channels is realized within the SIC by
a D-channel access procedure. Each
terminal can be given a certain
priority for D access. Via the echo bit,
which is the reflection of the received
D channel at the NT, it is possible for
the terminal to detect the status of the
D-channel. In order to try to gain
access over the D-channel, a terminal
has to see 8 to 11 consecutive ones in
the echo-channel. The exact number
depends on the priority given to the
terminal. When several terminals try to
gain access at the same time,
collisions occur on the S-bus. The
terminal that transmitted "one" but
sees a “zero” in the echo channel
detects the collision and loses the D-
channel access.
The terminal that transmitted the
"zero" gains the access. When a
successful D-channel message is
transmitted, the priority is decreased
by 1 in order to guarantee fairness
with the other terminals. The status of
the D-channel of the TE/LTT is
available at a device pin, or at the 5th
bit position of the monitor byte. This
enables the control of the D-channel
by an external HDLC controller.
At the NT/LTS side, the echo bits of
several NTs can be combined in an
external common echo bus (wired
AND) in an NT-star configuration. At
the LTS side, the same external
common echo bus can be used to
share an external HDLC controller
between several LTS SICs.
SIC
<= 1.2 Km
T
R
SIC
V* GCI
T
R
T
R
V* GCI
TE/LTT
NT/LTS
Fig. 2.6 : Point to Point Configuration
<150 m
T
R
SIC
V* GCI
T
R
T
R
SIC
TE # 1
SIC
TE # 8
MAX 8
T
R
TERMINATING RESISTOR
of 100
NT/LTS
Fig. 2.7 : Point to Multipoint Configuration
6
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Analog
transmitter
s_transmitter
DPLL
s_receiver
FL detection
M control
buffer
activity
detector
7680 kHz
oscillator
asynchronous
power up/down
V*/GCI
DIN
DOUT
DFR
DCLK
status
controller
Analog
receiver
MUX
C/I
S, Q
B, D
B, D
SX
P
S, Q
SX
N
SR
P
SR
N
XTI
XTLO
B, D
B, D
CHP boundary
Fig. 2.8 : Block Diagram
2.3 The MTC-20172
SIC Operation
Overview
The block diagram is shown in fig.2.8.
Data from the So-interface is received
by the SIC receiver, which has a
balanced input, an AGC stage, a filter
and comparators with dynamically
adapted thresholds. The timing of the
received S0-frame can either be a
fixed (Only NT/LTS) or adaptive
timing.
In the fixed timing case, the timing is
locked to the transmitted frame, and
the tolerable phase delay on the
received So-frame is limited. In
adaptive timing mode, delays up to
48 µs can be tolerated. The start of
the received frame is detected in the
FL-detection unit. An adaptive
algorithm is used for compensation of
the slope of the FL transition. A digital
PLL recovers the received bit clock
(192 kHz).
A second digital PLL generates the
transmit bit clock (192 kHz), which is
locked to the GCI frame in the case of
NT/LTS, or is locked to the received
So-frame in the case of TE/LTT
applications. It is possible to com-
pensate external circuits (e.g. filters)
by adjusting the internal phase of the
bit clocks by means of a device pin,
or by means of a register accessible
by the monitor channel.
These circuits work with a 7680 kHz
±100 ppm clock. This clock can be
delivered to the SIC by an external
generator, a UIC (for NT modes), or
can be generated by an on-chip
oscillator.
The serial B and D data from the V*
GCI digital interface is stored into a
buffer with a dynamic pointer
structure, and is presented to the
S_transmitter where the So-frame
formatting is done. In the other
direction, the S_receiver unit dis-
assembles the received So-frame. The
B and D data are stored in the buffer
and multiplexed together with M, C/I,
MX and MR into a digital V* GCI
frame. The pointer structure of the
buffer guarantees a minimum round-
trip delay in NT, LTS and TE modes,
and is able to compensate the clock
wander in LTT mode. If the clock
wander becomes too big, a warning
is given in the C/I channel, and the
internal pointers are reinitialized.
Activation/deactivation procedures
are handled in the status controller.
Two basic modes are available: A V*
mode, compatible with the MTC-2072
SIC and other earlier ISDN devices,
and an GCI compatible mode.
The S/Q control module handles the
multiframing on the S and the Q
channel of the So-interface. Multi-
framing is enabled in NT/LTS mode
by a width modulation of the frame
synchronization signal DFR every 40th
GCI frame, a monitor programmable
register, or by an auxiliary device pin.
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MTC
20172
(Top view)
4
3
2
1
28
AUX
XTLI
XTLO
VSS
SCLK
MOD0
XTR1
SXP
VDD
AUX2
VDD
SRP
SRN
AUX1
RSTB
XTR3
AUX4
MOD2
MOD1
XTR4
DOUT
DCLK
DFR
DIN
XTR2
SXN
AUX3
XTR0
2.4 Test Modes
Summary
Two test loops may be closed in the
SIC, which depend on the selected
mode of operation. In both modes, all
three channels (B1, B2 and D) are
looped back as close as possible to
the So-interface.
Loop 2 (NT, LTS) is a transparent loop
(fig.2.9a) where the transmitted So-
frame is also switched on the S-bus.
Activation from the So-interface is not
possible.
Loop 3 (TE, LTT) is a non-transparent
loop (fig.2.9b) where the transmitted
So-frame is not switched on the S-bus
so as not to activate the NT/LTS.
Activation from the S-bus is possible,
and is indicated by a special code in
the C/I channel.
Both loops are initiated over the C/I-
channel and under control of a layer
2 component.
For further testing of the subscriber
line, two test signals can be
transmitted over the So-interface: A 96
kHz test sequence sending continuous
AMI marks, and a 2 kHz test
sequence sending single AMI marks.
Both test modes are under control of
the C/I channel and (in NT mode) by
means of device pins.
MTC
20172
1
2
3
4
6
5
7
8
10
11
9
22
21
20
19
18
17
16
15
13
12
14
VDD
SXP
SXN
MOD1
DOUT
DCLK
DFR
DIN
RSTB
XTR3
XTR2
MOD2
XTR0
MOD0
SCLK
VSS
XTALO
XTALI
SRN
SRP
AUX2
XTR1
Fig. 2.9 : Pin Descriptions
a) 22 PDIL : MTC-20172-PD b) 28 PLCC : MTC-20172-PC
7
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
The M control unit interprets and
responds to messages on the monitor
channel. Via this channel, access is
possible to the S/Q bits and
configuration registers. Observation of
some user-defined input pins is also
possible.
In order to reduce the power
consumption of the components
connected to the subscriber line, the
SIC may be switched to a power
down mode during idle periods. In NT
and TE modes, the internal clock
distribution and the oscillator are
turned off, and the power
consumption is less than 3 mW. The
component is automatically powered
up again during the line activation
procedure. The power consumption
when activated, with an applied DCLK
clock of 512 kHz is less than 50 mW
3.1 Package and
Dimensions
The MTC-20172 SIC is available in
two package styles. For specific
requirements, please contact your
Mietec representative.
28 pin plastic leaded chip-carrier
(28PLCC). Details on the DIL and
PLCC packages are shown in Figure
3.1 and in Figure 3.2 respectively.
8
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
3. Pin and Package Data
Fig. 3.1 : 22 pin DIL package and dimensions
Fig. 3.2 : 28 pin Square PLCC Package and dimensions
3.2 Pin Allocation and
Brief Description
Table 3.1 contains the pin number for
the each package style, the pin name,
I/O type, and a brief description. The
I/O column describes the
Input/Output buffer type used.
The 22 pin plastic DIC version
supports only the basic operation
mode.
The I/O types are :
P = Power pin
IO = Input and push-pull output with
tristate;
I = Input only;
IW = Input only, weak pull-up
resistor internally;
O = Push-pull output, tristate
possible;
OD = Output with open drain, no
internal pull-up;
ODP = Output with open drain,
internal pull-up in some
modes;
AO = Analog output;
AI = Analog input;
AT = Analog test pin, input and
output;
XI = crystal input; XO = crystal
output.
S = Strap (user), fixed to 1 or 0.
Some pins have different I/O function
or type depending on the mode, listed
in Table 3.3 and paragraph 3.5.
Detailed configuration of all pins in
paragraphs 4.11 and 4.12, Tables
4.1 and 4.2. The electrical I/O
properties are described in 9.5 and
9.6.
The pin configuration is found in
Figure 3.3 and 3.4.
9
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Fig. 3.3 : 22 pin DIP, Signal Names
Fig. 3.4 : 28 pin Square PLCC Package, Signal Names
Basic Mode
(Basic and External) *
* see 6.5
128
The extra pins of the 28 pin package
are not bonded in the 22 pin DIL: AUX
and VDD (pins 22 and 28) are
replaced by double bonding-wires to
the VDD and VSS pins. The XTR4,
AUX1, AUX3 and AUX4 have a weak
internal pull-up resistor, because they
are inputs, or are configurable as
inputs. This avoids a floating bonding
pad in the 22 pin package, which
would cause unnecessary leakage
currents on the input amplifier.
10
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table 3.1: Pin List and Description, 22 and 28 pin Package
28 22 pin
pin pin name I/O Description
2 1 VDD P Supply voltage +5V 5%
22 17 VSS P Supply voltage 0V
13 10 RSTB I Reset signal, inverted polarity
1 22 AUX2 AT Previously Rref input, analog I/O test pin,
preferably left UNCONNECTED
24 19 XTLI XI Clock input, crystal connection input
23 18 XTLO XO crystal output, not used when clock supplied
3 2 SXP AO S-Bus positive transmitter output
4 3 SXN AO S-Bus negative transmitter output
26 20 SRN AI S-Bus balanced receiver input
27 21 SRP AI S-BUS balanced receiver input
10 8 DIN I Serial Data Input GCI
7 5 DOUT O/ODP Serial Data Output GCI, pull-up 3.5
8 6 DCLK I(O) Clock signal GCI bus, (Output TE mode)
9 7 DFR I(O) Frame signal GCI bus, (Output TE mode)
16 12 MOD2 I/S Mode pin 2, \ to select NT/LT-S/LT-T/TE,
5 4 MOD1 I/S Mode pin 1, > clock families on GCI
20 15 MOD0 I/S Mode pin 0, / special features
14 11 XTR3 IO Extra bidirectional pins, for special modes,
11 9 XTR2 IO bus address selection or special extra
19 14 XTR1 IO outputs
17 13 XTR0 IO/ODP
21 16 SCLK IO Synchron. Clock (TE/LT-T), else strap/test
Extra pins for the 28 pin PLCC package
28 - VDD P/S Extra supply voltage +5V
25 - AUX P/S Extra supply voltage, strapped at 0V
6 - XTR4 IW/S TX phase adjust strap see 5.4.3
12 - AUX1 IO/ODP Extra auxiliary in/out, generic use possible
18 - AUX3 IO/ODP Extra auxiliary in/out, generic use possible
15 - AUX4 IO/ODP Extra auxiliary in/out, generic use possible
see 4.11
&
7.7.4
3.3 Input/Output Types in Function of the Modes
i = Input;
i* = Input, remark on compatibility,
see 3.6;
iw = Input, weak pull-up internally,
values see 3.6;
s = Input as Strap, fixed to 1 or 0;
o = Push-pull output, tristate
possible;
od = Output with open drain, pull-
up external;
odp = Output open drain, pull-up
internal, NT, speed 256
kbit/s;
iodp = I/O bus open drain, pull-up
internal, values see 3.6;
i? = Input, choice of type open, for
test purposes;
o? = Output, choice of type open,
for test purposes;
11
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table 3.2 : Input/Output types in function of the modes
XTR4
pos. MOD2 MOD1 MOD0 AUX4 AUX3 AUX1 SCLK XTR3 XTR2 XTR1 XTR0 DOUT DIN
TE 0 0 0 o od iw o i o o o o i
0 0 1 o od iw o i o o o o i
0 1 0 o od iw o i o o i o i*
LT T 0 1 1 o od iw o s=1 s=TS s=TS s=TS od i
0 1 1 o od iw o s=0 s=0 s=0 i o i*
NT 1 1 1 o od iw i i i i iodp odp i
LT S 1 0 0 iodp od iw s=0 i s=TS s=TS s=TS od i
1 1 0 iodp od iw s=0 i s=0 o s=0 o i*
1 1 0 iodp od iw s=0 i o o s=1 o i*
TE 1 1 0 o od iw s=1 i o o o od i
LT T o od iw o od i
1 0 0 s=1 s=TS s=TS s=TS
LT S iodp od iw i od i
NT 1 0 1 o od iw i i i i iodp odp i
1 1 0 o? o? i? s=0 io? s=1 io? s=0 o? i?
TEST 0 1 1 o? o? i? io? s=0 s=1 s=x io? o? i?
0 1 1 o? o? i? io? s=0 s=0 s=1 io? o? i?
MOD2 MOD1 MOD0 AUX4 AUX3 AUX1 SCLK XTR3 XTR2 XTR1 XTR0 DOUT DIN
XTR4
B
A
S
I
C
E
X
T
E
N
D
E
D
3.4 Values and Usage
of the Pull-Up
Devices
1) Pins Left Unbonded in the
22 Pin Package :
XTR4 is an input, left unbonded in the
22 pin package. To avoid a floating
input, it has an on-chip pull-up resistor
of nominally 100 k.
AUX1, AUX3, AUX4 have a standard
configuration shown in TABLE 3.3.
They can also be reconfigured as
generic inputs or as push-pull outputs,
see 7.7.4. To avoid a floating input in
the 22 pin package, they have an on-
chip pull-up resistor of nominally 50
k, which is compatible with the
speed of the DE bus function (see
4.11, 4.12) of the AUX4 pin.
2) Other Pins :
XTR0 pin serves as DE bus pin (see
4.11, 4.12) in certain modes. It has
an internal pull-up of nominally 50k
in those modes.
DIN: In the MTC-20172 SIC, the DIN
pin is a simple input.
DOUT: In the NT modes , the DOUT
pin is an open drain with an inte-
grated pull-up resistor of nominally 20
k. This allows data rates of 256
kbit/s. Higher data-rates will require
an additional external pull-up device
to be used.
12
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
3.5 Device Marking
PLCC
DIL
4.1 General Features
The main properties of the circuit are:
- Single Chip Transceiver on the
4 wire S-bus, single 5V supply;
- Handling of Basic Access at 144
kbit/s with 2B+D;
- Layer 1 functions of the CCITT I.430,
including E- and D-channel access
with priority in TE bus configuration;
- S-bus drivers with high impedance in
power-off (no supply);
- Improved S-bus balanced receivers,
compatible with the external
unbalanced PCBA circuitry
implemented in existing products;
- Handles attenuation on the S-bus up
to 15 dB (CCITT minimum=7.5dB);
- Exceeds 1 km point-to-point and 200
m bus range;
- Has both fixed timing and adaptive
timing as NT/LT-S;
- Can be used in LT-T mode, with
clock wander up to 18 ms;
- Operating power consumption < 50
mW;
- Stand-by power < 1.5 mW;
- Dynamically configurable to the
S- and the T-interface;
- S & Q bit channel on the S-bus,
written/read via GCI-M-channel;
- Handles GCI, V*, IOM1™ and
IOM2™ bus interfaces;
- Includes a maintenance M-channel
for all GCI modes;
- Connectable to HDLC devices in
TE/LT-T with access protocol;
4.2 Compatibility
The MTC-20172 SIC is a single
component, which can cover all
applications for an S-Bus device
without HDLC.
It is pin-compatible with MIETEC MTC-
2072 SIC and is functionally similar.
4.3 Improved Features
* The ternary S-bus receiver is
balanced, backwards compatible
with the unbalanced Mietec MTC-
2072 SIC, and with improved line-
length and noise immunity.
* The ternary S-bus drivers require a
series resistance, and have a high
impedance when SIC power is off.
Pulse overshoots are limited on-chip,
see 5.2.
* The serial bus is multifunctional,
supporting V*, GCI, IOM1™ and
IOM2™ timing, selected with straps
or automatically recognized.
* The GCI C/I-channel is
multifunctional, supporting the older
V* version of the Mietec MTC-2072
SIC, or the GCI version of newer
devices.
* GCI M-channel is added, e.g. for
reading/writing the S/Q channel,
and to select modes via software,
overriding the strapped modes or
the default state after reset; (new
feature).
* An ECHO bus allows pooling of
HDLC receivers on linecards (new
feature).
* Multiframing on the S-bus is
implemented (new feature).
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4. General Functional Description
The MTC-20172 SIC allows the con-
nection of terminals to this interface by
performing all layer 1 functions.
Note that in PABX/NT2 applications
the MTC-20172 SIC is configurable as
linked to either the S- or the T-
interface, while linked to the same
internal GCI bus.
4.5 General Description
of the S-Bus
Interface
The MTC-20172 SIC can be used on
the S-bus configured as a point-to-
point connection or as a passive bus.
The bus connection can handle up to
8 terminals. It is either a short bus with
the terminals dispersed over a length
of 200m, or an extended bus with a
cluster of terminals within a 25 m
range.
The chip handles full-duplex transmis-
sion of two B-channels (64 kbit/s
each) and one D-channel (16 kbit/s).
It handles also the echo E-channel, the
multiframing S and Q bits, ...
The MTC-20172 SIC contains all
circuit parts necessary for the
adaption of the S-interface, especially
transmitter and receiver stages.
- S-bus outputs are balanced,
allowing bus operation;
- S-bus inputs are balanced,
compatible with the Mietec MTC-
2072 SIC and other industry
standart devices;
- Out-of-band noise is filtered;
- RX has AGC and an adaptive
threshold, and corrects long-line
distortion by optimizing the sample
moment.
- NT/LT-T receiver bus type is
selectable: Short bus with fixed
timing, or adaptive timing for
extended bus or point-to-point.
The S-bus transceiver stages must be
connected to the bus via external
interface circuitry (2:1 transformer)
and protection against electrical
overstress due to foreign voltages. See
appendix A with application note.
When the MTC-20172 SIC is in an un-
powered state (supply voltage = 0 V)
the S-bus transmitter is high ohmic (see
CCITT I.430 8.5.1.2).
4.4 Overview of the
Use of the MTC-
20172 SIC in an
ISDN System
See Figure 4.1
The MTC-20172 SIC circuit is part of
the TE, the NT1, the NT2 at the S- and
the T-interface side. It can be used in 4
different positions:
1) NT mode: In the NT1 as master of
the S-interface towards terminal
equipment, or as master of the T-
interface, towards the NT2.
2) TE mode: at the terminal equipment
(TE) side linking the TE to S-interface in
the direction of the NT1 or NT2.
3) LT-S mode: Inside the NT2 (e.g. a
PABX) at the S-interface, which is
equivalent to the master position in the
NT1.
4) LT-T mode: Inside the NT2 (e.g. a
PABX) at the T-interface, which is
equivalent to the terminal position on
the S-interface.
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
ILC SIC
ILC SIC SIC UIC UICSIC SICILCILC
SIC UIC UIC
SO SO UKO
UKOSO
Public ExchangeNTPABX-NT2
GCI GCI
TE
TE NT Public Exchange
Different positions where the GCI Interface is used
Fig. 4.1 : FICA Applications
This is needed in LT-T and TE
applications, when multiple S-devices
are sourcing on the same S-bus (short
passive or extended bus).
In TE/LT-T, the S-bus transceiver
provides the D-channel access
protocol, in collaboration with an
intelligent HDLC transmitter at the GCI
bus side.
For details, please refer to chapter 5.
4.6 The GCI
Interface
At the digital control interface, the
MTC-20172 SIC is connected via a
bidirectional serial interface - a digital
bus called the General Circuit
Interface (GCI), which is similar to the
ISDN Oriented Modular (IOM™)
interface.
This bus is logically organized as
many parallel point-to-point links, each
at 256 kbit/s.
The description of the GCI bus is
available in separate documents.
Details are provided in chapter 6.
4.6.1 The Physical Organization
of the GCI Bus
The bus has a clock and a frame
signal for timing, and two data lines
(one for each direction).
In the TE mode, the clock and frame
are generated by the MTC-20172
SIC. Then the timing is slaved to the
S-bus and the network.
In the LT-T, the LT-S or the NT mode,
the MTC-20172 SIC receives timing
from the GCI interface.
In the LT-T, the MTC-20172 SIC must
handle jitter, wander and slip between
the GCI timing and the received S-bus
clock.
The actual timing and speed of these
4 signals exists in several flavours and
variants. The MTC-20172 SIC
performs all the different timing
variants of the V*, IOM1™ and
IOM2™.
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Data Sheet & Reference Manual
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4.6.2 General Content of the
GCI Bus
The GCI interface is organized with 4
channels at 64 kbit/s: B1, B2, M
(Maintenance or Monitor), and B1*
channel; Figure 4.2.
The B1 and B2 channels are
transparent, switched at 64 kbit/s.
In ISDN applications, the B1* channel
contains two D-channel bits, a 4 bits
C/I ‘command/indication’ channel
with the commands (towards MTC-
20172 SIC) or the indications (from
MTC-20172 SIC), and two extra bits
(MR and MX) to control the M-channel.
For details, please see chapter 6.
The D-channel contains HDLC-formatted
messages. It is transported transparently
(NT) or terminated by an HDLC
transceiver (LT-S/LT-T/TE). In the TE/LT-
T, a D-channel access protocol exists
for the S-bus, which is controlled by the
MTC-20172 SIC, and responded to by
the HDLC transmitter. Via the
command/indication (C/I) channel,
commands to and status indications
from the MTC-20172 SIC are
exchanged with a control element
(usually, a µ-controller) or with an other
uplink or downlink ISDN circuit.
Commands and indications are
debounced to avoid erroneous
behaviour.
Fig. 4.2 : Frame Structure GCI
The M channel is a 64 kbit/s channel.
It has a byte oriented structure, and
the content is indicated and
acknowledged with the MR and MX
bits - the two last bits in the B1*
channel. The content of the channel is
used to write and read the internal
MTC-20172 SIC registers. Its use is
optional in the MTC-20172 SIC.
4.6.3 Power-down on GCI
For maximal power saving, the GCI
bus can be halted completely and
reactivated asynchronously from either
side of the bus.
Section 4.9 gives a general
description of the power-down
features of the MTC-20172 SIC.
Chapter 6 gives the detailed
behaviour.
4.7 GCI Clock-
Synchronization in
the ISDN
Environment
In general, the downstream devices
are slaved to the upstream devices.
Upstream MTC-20172 SIC
(NT/LT-S):
A MTC-20172 SIC in the NT/LT-S
position is master of the S-bus, and
can sample the received (upstream) S-
bus frames with a receive clock at
exactly the transmitted frequency, but
with an unknown phase.
In the NT/LT-S mode the MTC-20172
SIC receives the GCI timing, and must
derive the 192 kHz S-bus bit-clock
from it. As the GCI timing is not
necessarily a multiple of 192 kHz, the
MTC-20172 SIC generates a 192 kHz
TX and RX clock from a crystal or from
a clock input at 7680 kHz (±100
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Data Sheet & Reference Manual
Rev. 1.1 February 1997
ppm). The 192 kHz clock is not a
pure division by 40 of the crystal
frequency, but is locked to the 8 kHz
frame signal of the GCI interface. This
is a DPLL action, where the 192 kHz
clock period can be adjusted by ± 1
1/40 every 250 µs. Note that jitter
on the 192 kbit S-bus signals is a
combination of the jitter on the 7680
kHz before the DPLL and the effects of
the DPLL locking to the GCI 8 kHz
frame.
The S-bus RX clock in fixed timing
(short passive bus) is derived from the
same crystal, with the same frequency
correction as the transmit clock but
with a phase offset. The corrections of
1/40 of a bit period are used in an
open loop mode here.
The S-bus RX clock in adaptive timing
(extended bus, point-to-point) is also
derived from the same crystal.
However, the receiver must optimize
the symbol sampling moment. This is
an extra phase correction, which
tracks wander and jitter of the
received data.
The receiver tracks the RX data by
locking on the F/L transitions.
Note: The timing stays identical for an
internal analog loop from TX to RX,
because then the MTC-20172 SIC
uses adaptive RX timing as well. Even
an external S-bus loop can be
applied, provided that the receiver
does NOT work with fixed RX timing.
Conclusion: in NT/LT-s, the MTC-20172
SIC has 3 different clocks, which are
locked in frequency, but with unknown
phase relation. Because the clocks are
derived via PLL and DPLL blocks, the
phase relation is not constant, but has
some jitter and wander.
Downstream MTC-20172 SIC
(TE):
In the TE mode, the timing is slaved to
the S-bus and the upstream network.
The MTC-20172 SIC generates a
192 kHz RX sampling clock from a
crystal or from a clock input at 7680
kHz 100 ppm. This 192 kHz is
locked to the 4 kHz frame signal of
the S-bus. This DPLL action adjusts the
192 kHz clock period 1 1/40 every
250 µs.
The GCI clock and frame are
generated by the MTC-20172 SIC,
derived from the received S-bus
timing. The transmit clock is also in
fixed relation to the receive timing. To
correct for external delays, the phase
of the TX clock is adjustable, see
section 5.4.3.
Conclusion: in TE mode the MTC-
20172 SIC has all clocks locked to
the 192 kHz RX S-bus data, with a
fixed deterministic phase relation,
except when loops are applied as
explained below.
Downstream MTC-20172 SIC
(TE) in analog loop:
When the downstream MTC-20172
SIC is looped (analog internal loop,
not transparent) the linking and phase
relation of the different clocks is
completely different. The MTC-20172
SIC uses its local crystal as master
clock and derives the S-bus TX and RX
clock and GCI timing. The S-bus
transceiver behaves as an upstream
device. However, it monitors the RX
signals to activate if desired.
Moreover, the loop is not transparent,
i.e. no signal is sent to the actual S-bus.
Downstream MTC-20172 SIC
(LT-T):
In the LT-T, the S-bus and the GCI
timing are both enforced on the MTC-
20172 SIC. They are not necessarily
synchronized or even locked.
To allow the GCI clock to be
synchronized on the S-bus clock, the
MTC-20172 SIC has a dedicated
clock output, called CP or SCLK,
locked to the S-bus clock (see 4.11
and 4.12). This signal can be used in
the PABX/NT2 system to lock the GCI
timing to the ISDN. Once this
synchronization (external to the MTC-
20172 SIC) is active, the S-bus clock
and the GCI timing will only wander
and jitter. MTC-20172 SIC will accept
wander of 18 µs.
Conclusion: In the LT-T, the S-bus
receiver and transmitter timing are
slaved to the S-bus and the upstream
network, as in the TE mode. To accept
wander of 18 µs, the MTC-20172 SIC
has a long FIFO buffer between the
GCI and S-bus side. If both clocks
have different frequencies, the MTC-
20172 SIC handles slips. (Details in
6.5.4).
Downstream MTC-20172 SIC
(LT-T) in analog loop:
When the downstream MTC-20172
SIC is looped (analog internal loop,
not transparent), the linking and phase
relation of the different clocks is
completely different. The MTC-20172
SIC uses the GCI timing as master,
locks X-tal to the GCI frame, and
derives the S-bus TX and RX clock from
the crystal. The clock relationships
inside the MTC-20172 SIC in LT-T
position during the analog loop is
identical to the LT-S device. However,
it monitors the RX signals to activate if
desired. Moreover, the loop is not
transparent, i.e. no signal is sent to
the actual T-interface.
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Data Sheet & Reference Manual
Rev. 1.1 February 1997
4.8 Clock Speed
The master clock runs at 7680 kHz,
±100 PPM.
Internally, the S-bus transceiver part
runs at 192 kHz. This is derived from
the master clock, but locked to the
ISDN network clock with a phase
locked loop, adjusting one 7 MHz
period every 250 µs. The ISDN
network clock is sent downstream via
the S-bus or the GCI interface.
The GCI part runs at the clock speed
of its interface, which is minimally
512 kHz.
4.9 Power Saving /
Deactivation of
MTC-20172 SIC
The MTC-20172 SIC is controlled via
the GCI interface. This interface is
designed to be shut down and
consequently reactivated in TE and
NT modes. Shutting the bus down is
commanded by the controller on the
bus. Once the command is
acknowledged, a fixed procedure is
used to halt the clock (either by MTC-
20172 SIC in TE, or by the controller
in NT). Reactivating the bus can be
done by the MTC-20172 SIC or the
controller. Details are given in section
6.2.
When the GCI bus is going to be shut
down, the S-bus transceiver is put to
idle also. The S-bus transceiver
enables an asynchronous signal
detector, which can reactivate the
MTC-20172 SIC on receipt of INFO
via the S-bus. The MTC-20172 SIC
then shuts down the internal 7 MHz
clock distribution, and also the crystal
output. If the clock is external, it may
be also be put to idle, after the GCI
bus is idle.
The MTC-20172 SIC can receive
activation via the S-bus during the
process of shut down via the GCI bus.
4.10 MTC-20172
SIC Activation
Activation of the MTC-20172 SIC
depends on the position and mode.
4.10.1 MTC-20172 SIC
Activation in NT Mode
Activation through the S-bus will be
seen by the signal detector. The MTC-
20172 SIC does not need crystal
input or GCI clock to activate the GCI
interface, which it does by
asynchronously pulling the data line
low. The master on the bus answers
with GCI clock and frame, followed
by commands via the C/I channel.
The bus master also delivers the crystal
frequency if it is generated externally
to MTC-20172 SIC, simultaneously
with GCI activation.
Activation through the GCI bus
consists of clock and frame delivery,
followed by commands via the C/I
channel. MTC-20172 SIC will activate
the S-bus transceiver according to the
commands, including the crystal
oscillator. If the master clock is
generated externally it must be
delivered to MTC-20172 SIC. Note
that the internal clock distribution to
the S-transceiver section is delayed for
2 ms (using the GCI frame clock), to
allow the crystal clock to stabilize.
4.10.2 MTC-20172 SIC
Activation in TE Mode
Activation through the S-bus is
possible. The signal detector enables
the crystal, the GCI clock and frame is
activated, the receiver hunts for
synchronization, indications and
commands are exchanged via the C/I
channel and the MTC-20172 SIC
awaits further commands.
On activation through the GCI bus,
the controller pulls the data line low
(timing request). The MTC-20172 SIC
enables clock and frame, and C/I
codes are exchanged between the
MTC-20172 SIC and the controller.
One major difficulty exists: Once the
MTC-20172 SIC has acquired
synchronization on the downlink data,
the GCI frame must be adjusted to the
received frames. This is needed to
minimize transport delays of the B-
channels. There is an optimal fixed
relation between the received S-bus
frame and the GCI frame, see 5.5.2.
The locking of the GCI frame to the S-
bus frame causes a jump of the GCI
frame pulse. To limit the number of
phase jumps, the MTC-20172 SIC
only adjusts the free-running GCI pulse
when full synchronization on the S-bus
frames is acquired.
4.10.3 MTC-20172 SIC
Activation in LT/S and LT/T
Modes
In this case, the GCI bus cannot be
shut down.
The GCI clock and frame run
continuously, but the MTC-20172 SIC
can be forced in a low power state
via the dedicated command. This
command deactivates the S-bus
transceiver. The crystal oscillator and
the internal clock distribution stay
enabled. The asynchronous signal
detector is the only active part in the
S-bus transceiver, the GCI part will
react on new C/I channel commands,
but runs no other activity internally.
4.10.4 Crystal Oscillator
Operation
In the LT-T/LT-S modes, the crystal
oscillator is permanently on, together
with the clock distribution.
In the NT mode, the crystal oscillator
is OFF during the power-down state,
and the crystal clock distribution at
wake-up is delayed after activation by
2 ms, by using the GCI frame clock.
In the TE-mode, the crystal will be shut
down in the power-down state, except
when the clock signals are requested
to stay active via the ENCK- pin, see
4.12.
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Data Sheet & Reference Manual
Rev. 1.1 February 1997
4.11 Modes
of Operation
The TABLE 4.1 shows all Basic and
Extended modes, as they are
implemented in the MTC-20172 SIC.
The mode is determined by the state of
the MOD2-0, XTR0-4, SCLK pins, as
shown in Table 4.2.
The range of the DCLK clock is
extended to any allowed GCI value,
i.e. any multiple of 16 kHz above
512 kHz. The AUX1-4 pins offer extra
input and output signals, as explained
in 4.12.
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Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table 4.1.a: Basic modes of operation with the MTC-20172 SIC
APPLICATION
TE TE TE LT-T LT-T NT LT-S LT-S LT-S
Operation Inverted Inverted V* GCI V* V* GCI V* V*
of IOM Mode Mode Mode Mode or Mode Mode Mode or Mode Mode
interface Inverted Inverted
Mode# Mode#
MOD2 0 0 0 0 0 1 1 1 1
MOD1 0 0 1 1 1 1 0 1 1
MOD0 0 1 0 1 1 1 0 0 0
DCLK o: o: o: i: i: i: i: i: i:
512kHz* 512kHz* 512kHz* IOM V* V* V* V* V*
DFR o: o: o: i: i: i: i: i: i:
8 kHz* 8 kHz* 8 kHz* 8 kHz 8 kHz 8 kHz 8 kHz 8 kHz 8 kHz
SCLK o:* o:* o: o: o: i: /SCZ i: fixed i: fixed i: fixed
(CP) 1536kHz 1536kHz 512kHz* 512kHz* 512kHz* at 0 at 0 at 0
XTR3 i: ENCK i: ENCK i: ENCK i: fixed i: fixed i: BUS i: BUS i: BUS i: BUS
(X3) at 1 at 0
XTR2 o: o: o: ECHO i: TS2 i: fixed i: /SSZ i: TS2 i: fixed o:
(X2) 2560kHz 1280kHz at 0 at 0 192kHz*
XTR1 o: o: o: i: TS1 i: fixed i: DEX i: TS1 o: o:
(X1) 3840kHz 3840kHz 3840kHz at 0 7680kHz 7680kHz
XTR0 o: RDY o: RDY i: CON i: TS0 i: CON i/o: DE i: TS0 i: fixed i: fixed
(X0) at 0 at 1
AUX4 o: o: o: RDY o: RDY o: RDY o: i/o: DE i/o: DE i/o: DE
AUX3 o: BER o: BER o: BER o: BER o: BER o: BER o: BER o: BER o: BER
AUX2 i: i: i: i: i: i: i: i: i:
XTR4 i: X4 i: X4 i: X4 i: X4 i: X4 i: X4 i: X4 i: X4 i: X4
AUX1 i: i: i: i: i: i: MFD i: DEX i: DEX i: DEX
*: Indicates signals synchronized with the So-Interface
#: Automatic selection between inverted and GCI mode o: = output
i: = input
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table 4.1.b : Extended modes of operation of MTC-20172 SIC
APPLICATION
TE LT-T LT-S NT
Operation GCI GCI or GCI GCI
of GCI Mode Inverted# Inverted# Mode or
interface Submodes Inverted
selected in SW Mode#
MOD2 1 1 1
MOD1 1 0 0
MOD0 0 0 1
DCLK o: * i : i : i:
1536kHz V* V* V*
DFR o: i: i: i:
8kHz* 8 kHz 8 kHz 8 kHz
SCLK i: fixed i: fixed i: SSZ
(CP) at 1 at 1
XTR3) i: ENCK o: * i: BUS i: BUS:
(X3) 1536kHz
XTR2 o: * i: TS2 i: SSZ
(X2) 768kHz
XTR1 o: PCK i: TS1 i: DEX
(X1) 32kHz*
XTR0 o: RDY i: TS0 i/o: DE
(X0)
AUX4 o: o: RDY i/o: DE o:
AUX3 o: BER o: BER o: BER o: BER
AUX2 i: i: i: i:
XTR4 i: X4 i: X4 i: X4 i: X4
AUX1 i: i: i: DEX i: MFD
*: Indicates signals synchronized with the So-Interface
#: Automatic selection between inverted and V* mode
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table 4.2 : Basic and Extended mode-selection pins in MTC-20172 SIC
pos. bus type MOD2 MOD1 MOD0 SCLK XTR3 XTR2 XTR1 XTR0
TE inverted 0 0 0
inverted 0 0 1
V* 0 1 0
LT-T GCI/inverted 0 1 1 1 TS2 TS1 TS0
V* 0 1 1 0 0 0
NT V* 1 1 1
LT-S GCI/inverted 1 0 0 0 TS2 TS1 TS0
V* 1 1 0 0 0 0
V* 1 1 0 0 1
TE GCI 1 1 0 1
LT-T
GCI/inverted 1 0 0 1 TS2 TS1 TS0
LT-S
NT GCI/inverted 1 0 1
GCI/inverted : Multiplexed mode, with multiple GCI channels;
automatic type recognition, using frame signal;
automatic recognition of clock frequency.
B
A
S
I
C
E
X
T
E
N
D
E
D
4.12 Functional
Description of the
Special Signals
The XTRi and AUXi pins have different
functions depending on the modes, as
described in the previous paragraph
and TABLE 4.1.
In Alphabetical Order
BER : Bit Error Rate: each excessive
violation seen during the S frame
between position 14 and 48 indicates
a link transmission problem, except in
uplink frames during multiframing (see
5.1.7). Each error forces this BER
output low for one S-bus bit period. All
BER outputs can be tied to a single
bus; see also 5.10.
BUS : Bus type configuration, "1" =
short bus with fixed timing, "0"
adaptive timing for extended bus or
point-to-point (NT/LT-S), overridable
via the GCI M-channel. It is preferable
to tie the BUS strap to the fixed
voltage via a resistor, because this pin
is also used as the CP signal output in
the extended modes.
CEB : Other name for the DE signal.
CON : Indicates connection to the S-
bus, enables INFO1 (TE and LT-T).
INFO3 transmission in response of
INFO2 or INFO4, is allowed without
CON after synchronization. This
signal in NOT overridable via the GCI
M-channel.
CP : In the TE and LT-T modes, the CP
pin is a clock locked to the S-bus data
frames, see TABLE 4.1. This clock can
be disabled via the monitor channel,
see 7.7.3. This simplifies clock
selection logic which must route only
one CP clock signal out of many
active T-interfaces, to the PABX or NT2
clock system. In the extended modes
the synchronized "CP" clock signal is
put on pin XTR3. Details on all
available clocks and their timing in
9.6.
DE : D-channel echo bus (I/O),
enabled by DEX or monitor command;
(NT and LT-S). All synchronized S-bus
transceivers are delivering the
received upstream D bits on this bus
and sample the common echo bit via
this bus. See also 5.6.
DEX : D-channel echo bus enable (NT
star configuration, LT-S HDLC pooling
configuration) See also 5.6. Strap,
1=enable, 0=disable; combined with
DEX register bit via the GCI M-
channel, see 7.7.3.
ECHO : This output reproduces the E-
bits in the TE-mode, from the received
S-bus data. These bits are
synchronized with the D channel on
the GCI data line. Used by intelligent
HDLC controller, to start and abort a
message; see 5.7.8.
ENCK- : When at 0, this input
enables the crystal, the GCI bus timing
and all other related clocks always (TE
mode). When C/I command code
goes to idle (1111) the bus is not shut
down. Related to detailed GCI power-
down, 6.2.
LP- : Loss of Power input and output;
these signals are NOT IMPLEMENTED
in the MTC-20172 SIC.
MFD : Multiframe Disable when 1,
internal weak pull-up, allows
multiframing via strap or digital
control signal; overridable via monitor
channel; see 5.9.2.
RDY : D-channel access protocol
status in bus (TE and LT-T), signals the
anticipated availability of the D-
channel to an intelligent HDLC
transmitter. "1" = clear to send; "0" =
occupied or busy. See also 5.7.3.
SCZ- : Send Continuous binary zeros,
inverted polarity; NT mode only,
forces a test signal on the S-bus
output, overrides C/I, activates the
GCI bus to ensure crystal input active.
SSZ- : Send single zeros, inverted
polarity; NT mode only, forces a test
signal on the S-bus output, overrides
C/I commands, activates the GCI bus
to ensure crystal input active.
TM1- : Test Mode 1 (inverted) =
SSZ-, send single zeros.
TM2- : Test Mode 2 (inverted) =
SCZ-, send continuous zeros.
TS2-0 : Time slot number on the GCI
bus (LT modes, mux'ed), represent a
binary number 0 to 7; straps.
X4 : Extra strap input.
OTHER SIGNALS, non-digital, not
dependent on the mode:
AUX : Strap/extra power supply,
see 3.4.
Rref : Not used; position used as test
for production test.
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5. Detailed Operational Description
of The S-Bus Interface
Fig. 5.1 : S Frame Structure
Introduction
An overview of the functional environ-
ment is given in chapter 4. In this chap-
ter we give external and internal opera-
tional details of the S-bus interface.
Detailed interface timing and electrical
specifications are given in chapter 9.
5.1 General
Characteristics
The S-interface realizes full-duplex
transmission of two B-channels
(64 kbit/s each) and one D-channel
(16 kbit/s). In addition, the S-interface
allows controlled access to the com-
mon D-channel and the activation/
deactivation of each connected
device.
5.1.1 Transmission Rate
The nominal transmission rate is 192
kbit/s in each direction. There is no
requirement for special bit sequences
in the B-channels.
5.1.2 Frame Structure
Data is transmitted within a frame of
48 bits in each direction. The nominal
frame period is 250 µs, which gives a
frequency of 4 kHz. The frame
structure is not dependant on 'bus' or
'point-to-point' configuration. The
frame structure is shown in Figure 5.1.
5.1.3 AMI S-bus Coding
(general in RX and TX)
For both directions, a pseudo-ternary
coding (AMI) is used. A binary '1'
(high level logic) is coded as 'no
signal' whereas a binary '0' state is
represented by alternating positive
and negative pulses (see Figure 5.2).
The polarity inversions, coupled with a
minimal density of marks per frame,
reduce the low frequency components
of the signal. The 4 kHz frame always
starts with a positive pulse (F-bit),
followed by a negative balance bit L.
5.1.4 Balance Bits
Inside the frame, several balance bits
are present serving two purposes:
1) In both directions, they guarantee
that the polarity of the first bit or F-
bit is constant. They also increase
the mark density on the link.
2) Moreover, in the uplink direction,
the bits in the frame can be
generated by different terminals.
Therefore, the frame is subdivided
into groups of bits, each sent by a
single terminal, and terminated also
with a balance bit. The first binary
'0' of each group of bits (except for
the framing signal) is coded as a
negative pulse. The balance L-bit
terminates those group with a
positive mark if needed, to avoid
violations of the mark inversion
scheme. This allows the different B
and D channel bits to be sent by
different transmitters on a bus,
because the AMI polarity is always
fixed. In this way, no AMI violation
can be caused by the multipoint
nature of the BUS.
5.1.5 AMI Violations for Frame
Synchronization
For synchronization purposes the AMI is
violated twice per frame. A 48 bit
frame always starts with a positive pulse
(F-bit) followed by a negative balance
bit L. The F-bit is a violation, because
the last mark of the previous frame is
positive also. The first binary '0'
following a framing signal (F,L) is
always negative, and is a second
violation.
5.1.6 Frame Synchronization;
Distance Rule
There are two AMI violations in the
frame: The F-bit at the beginning is at
a fixed position. The second violation
must follow the F bit within 13 bit
positions, because the frame contains
an FA (auxiliary flag) at position 14,
which is a binary 0, even if all other
bits (2 to 13) are binary one.
After the FA, the next violation will be
the F flag itself, at a distance much
larger than 13 bit positions. This
distance rule allows for fast and
reliable frame flag detection
5.1.7 Frame Synchronization;
Multiframing Exceptions
AMI violation delay in multiframing:
At the TE/LT-T position, the received
FA bit is occasionally a binary 1 in
case of multiframing (see 5.9).
However, the N bit at position 15 is a
binary one, because it is the binary
inverse of the FA (see 5.1.11.1). This
guarantees a second violation within
14 positions after the F bit.
AMI violation exception in
multiframing:
At the NT/LT-S position, the received
FA bit is occasionally a binary 1 in
case of multiframing. FA is followed
by a balance bit L, which is then also
at binary 1. If all B and D bits
between F-L and FA-L are also at
binary 1, then there is no second
violation within the 14 positions. If the
remaining bits (B and D channels) are
also at 1 in the remainder of the 48
bit frame, then the second violation
will be absent, and next F bit will not
be a violation! This can delay the
synchronization, and could trigger an
INVALID loss of synchronization.
The delayed synchronization during
multiframing is unavoidable.
To avoid an invalid loss of sync at the
NT/LT-S when multiframing is on, all
incorrect second violations (too late or
missing) in the uplink direction are
ignored if the FA bit was a binary 1 in
the corresponding 48 bit frame in the
downlink direction. Missing violations
at the F bit position are ignored if the
preceding 48 bit frame (downlink)
had the FA bit at one.
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Fig. 5.2 : S Coding with AMI
5.1.8 Synchronization
Principles, with Adaptive
Bit-timing
1) The receiver first finds the AMI
violations by oversampling.
2) Immediate bit-synchronization is
given by the F-L transition.
3) The distance rule of the next
violation within 14 positions is
used to validate the F-bit.
4) Frame synchronization is acquired
after 3 correct frames, with a
correct F-bit violation and a
second one within 14 bit
positions.
5) The F-L transition of each frame
locks a DPLL based on the crystal
frequency in the TE/LT-T case. In
the NT/LT-S, the F-L transition
determines the adaptive bit
sampling.
6a) At TE/LT-T, loss of sync after two
frames not having F violation, or
the second violation not following
the distance rule at 14 bit. After
the loss of sync, the TE/LT-T sends
idle (INFO0, uplink).
6b) At NT/LT-S, loss of sync after two
frames not having F violation, or
second violation following the
distance rule (at 14 bits), when no
multiframing is active. The
downlink signal stays active, but
changes automatically from
INFO4 to INFO2. In the case of
multiframing, the missing second
violation within the 14 bit
distance, or the missing violation
at the next F bit (for uplink frames
with the corresponding downlink
FA bit at binary 1), is ignored.
5.1.9 Synchronization
Principles, Fixed Bus Timing at
NT/LT-S
On a short passive bus, the position of
the bit sampling can be fixed. The
points 3), 4) and 6b) of the previous
paragraph are executed. No
oversampling is done, no DPLL action
is needed to track the F-L edge. Note
that the fixed timing is changed
automatically to adaptive timing,
when internal analog S-bus loops are
requested. When EXTERNAL S-bus
loops are used (e.g. for production
test), only adaptive timing is suitable.
5.1.10 Pulse Polarity in the S-
bus Frame
The receiver is polarity independent.
The transmitter in NT and LT-S mode
has no polarity requirements. The
transmitter in TE/LT-T must have a
fixed polarity to allow a bus operation
with multiple sources. See also 5.2.1.
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5.1.11 Transmitted Frames:
Depending on the activation state of
the interface, the MTC-20172 SIC can
transmit different signals called INFO
0, 1, 2, 3, and 4. Moreover, two test
signals are defined
5.1.11.1 Details on Downlink
Frames: Network to Terminal
The downlink Frames transmitted by
upstream devices contain an E-bit.
During INFO4, the E-bit is the echoed
D-channel bit received from the
downstream devices, see 5.6. This D-
echo-channel is used for the D-channel
access procedure, see 5.7.
Two L-bits are used for DC-balancing,
after the F-bit and the last bit the
frame. In downlink direction some
special bits are used, see Figure 5.1:
- A-bit used for activation (A=1 for
INFO4, A=0 for INFO2);
- S-bit coded as binary zero, if no
multiframing active;
- N-bit coded as N = .NOT. FA
(applies to INFO2 and INFO4);
- M-bit at binary zero, except when
multiframing ( 5.9);
- FA-bit, additional flag (bin. zero),
except when multiframe.
Without multiframing active, S, FA, M
bits are binary zeros. Multiframing is
allowed to be active during INFO2
and INFO4, and influences the S, FA,
M bits as described under 5.9.
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Signals from network Signals from terminal
to terminal to network
INFO0 No signal, open circuit INFO0 No signal, open circuit
INFO2 Frame with all bits of INFO1 Continuous signal with
B, D, and E-Echo channels, the following pattern :
and a bit at binary zero, positive zero,
FA, M, S, N and L bits negative ZERO,
six ONEs follow the coding
rules of 5.1.11.1
INFO4 Frame with operational INFO3 Synchronized frames with
data on B, D, and E-Echo operational data on B, D
channels. Bit A set to channels. FA and L bits
binary ONE. FA, M, S, N, L according to normal coding
bits follow the coding rules of 5.1.11.2
rules of 5.1.11.1
TEST1 Send Single Zeros (SSZ), TEST1 Send Single Zeros (SSZ),
AMI marks, 250 µs distance AMI marks, 250 µs distance
forced via pin (NT) or C/I forced via pin (NT) or C/I
TEST2 Send Continuous Zeros TEST2 Send Continuous Zeros
(SCZ), alternating marks, (SCZ),alternating
marks forced via pin forced via pin (NT) or C/I
(NT) or C/I
The B-channel and D-channel are transparently transmitted on the S-bus.
When idle, these channels are all binary 1.
5.1.11.2 Uplink Frames:
Terminal to Network
The INFO3 frame transmitted at
terminal-side consists of several
groups of bits, each of them DC-
balanced by an adjacent symmetry-bit
L.
See Figure 5.1.
The uplink D-channel requires an
access protocol, detailed in 5.7.
Downlink multiframing influences the
FA-bit in uplink (Q-channel): If the
MTC-20172 SIC receives the FA-bit
as binary 0 (electrical mark), it will
always answers with binary 0. If the
MTC-20172 SIC sees the FA-bit as
binary 1 it answers with binary 1,
when multiframing is not active.
When using multiframing the FA-bit is
coded as described in section 5.9.
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5.2 S-BUS Transmitter
Analog Blocks
5.2.1 Polarity
The polarity is such that the F bit puts
the SXP pin at a positive voltage
relative to the SXN pin.
5.2.2 MTC-20172 SIC Drivers,
External Transformer and
Circuits.
In the TE/LT-T position, 8 S-
transmitters must be able to send
information simultaneously on the S-
bus in uplink direction. For this reason
the drivers are current limited voltage
sources, with a minimal series
resistance when the current limitation
is not active.
The outputs are balanced. The pulse
height is a linear function of the
supply voltage. The pulse shape has
5% margin around the nominal
height, when the MTC-20172 SIC
supply voltage is nominal. When the
supply voltage has a 5% range, the
pulse will be within the 10% tolerance
of the CCITT recommendations.
See Figures 5.3 and 5.4.
The drivers are high ohmic when
transmitting a binary one, or when
the chip is not powered.
Fig. 5.3 : Pulse Mask 50 Ohm
Impedance:
The drivers are a low-ohmic voltage
source, connected with a series
resistance to a transformer with a 2:1
winding ratio. At the SIC side of the
transformer, the 50nominal impe-
dance of the bus is seen as a 200
resistance. The nominal pulse on the
transformer is 1.5 V, at 7.5 mA. The
open circuit voltage is 2.1 V (140 %
of 1.5 V). The total driving resistance
of the SIC plus the external series
resistor must be 80. (See 5.2.4).
When the bus impedance is lower
than the required 50, e.g. when
shorted or when drivers are driving
opposite polarities, the output current
when driving a binary 0 (electrical
mark) is limited below 13 mA in
absolute value.
Longitudinal signals, protection
circuitry and further details under
electrical characteristics, see 9.5 and
12
5.2.3 Ternary Drivers:
High-Ohmic State when
not Powered.
The S-bus drivers of the SIC will be in
a high-ohmic state when not powered,
i.e. when the bus is active, but the SIC
is not powered. This is required to
fulfil the CCITT requirements on output
impedance in the TE (or LT-T) position,
in parallel with other SICs. (This is
achieved by using only n-type devices
for the complete driver stage, because
push-pull CMOS drivers always have
parasitic diodes to both power supply
and ground. These diodes limit the
voltage between the SXP and SXN
pins to less than 1.2V, by shorting the
differential voltage via the power pins.
On the S-bus, the amplitude of the
voltage would drop to 0.6 volts, while
the CCITT I.430, 8.5.1.2 requires
currents below 0.6 mA when signals
with peak amplitudes of 1.2 V are
applied on the S-bus).
5.2.4 Ternary Driver:
Compatibility and Evolution
On the SIC, the ternary drivers require
two series resistors of around 34
between with the balanced output
drivers. The 34includes the real part
of the impedance of the sending
transformer. When an MTC-2072 SIC
is replaced by the MTC-20172 SIC,
the extra resistors must be added to
the PCB.
Originally the MTC-2072 SIC drivers
were current sources, driving a known
7.5 mA in the transformer, with a
simple voltage limitation. In the MTC-
2072 SIC, a reference resistor (Rref) is
used to generate the nominal 7.5 mA
current.
The voltage drive with 80in series
limits overshoots on single pulses,
compared to the older high-ohmic
current drive. However, the peak-
voltage on the bus goes to 140%,
when multiple S components are
driving the bus simultaneously.
Note also that the 80series
resistance could be considered
necessary to fulfill the CCITT
requirements on the driver output
impedance when transmitting a zero,
although the actual measurement
technique specified by the CCITT is
questionable, when the SIC drives the
specified nominal 400impedance.
(CCITT I.430 8.5.1.2).
5.2.5 S-bus Transmitter Timing
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Fig. 5.4 : Pulse Mask 400 Ohm
and Framing; Jitter
The transmitter data are sent at 192
kHz. The 192 kHz is derived from the
crystal frequency of 7 MHz, by
division by 40. The transmitter framing
is at 4 kHz. The timing is slaved to the
downlink clocks, the 4 kHz S-bus
frame is locked in phase to the
available downlink framing, see 5.5.
5.2.5.1 Transmitter Timing and
Framing at the NT/LT-S
With a DPLL, the 192 kHz clock is
locked to the GCI interface at the
NT/LT-S, by synchronizing the S-bus
frame with the GCI frame. The DPLL
locks the falling edge of the F/L frame
signal on the GCI frame signal, see
5.5. Jitter will be according to the
CCITT I.430 8.3.
5.2.5.2 Transmitter Timing and
Framing at the TE/LT-T
The 192 kHz is locked, with a DPLL, to
the downlink data. The transmit clock
frame reference is derived from the RX
F/L edge, as explained under
5.3.12.3. Jitter will be 2.5 % of a bit
period when receiving a clean input
signal. In the presence of noise and
jitter on the downlink data, the uplink
jitter will be larger. However, the TX
clock is derived with a DPLL which can
only adjust one 7 MHz period every
S-bus frame, which limits jitter
enhancement.
5.3 S-BUS Receiver:
Analog Parts and
Synchronization
The MTC-20172 SIC has an improved
ternary receiver. It is fully balanced, to
better reject longitudinal noise. It
handles higher attenuations on the S-
bus, with adaptive thresholds.
5.3.1 Transformer and Other
External Devices.
The receiver is connected to the S-bus
via a transformer with a 2:1 ratio,
similar to the transmitter. Using a
lower winding ratio reduces the useful
signal sensitivity. Moreover, the bit
detection thresholds will be not opti-
mal, especially for the short bus appli-
cations. The input transformer (toge-
ther with other filter elements) must
also reject longitudinal noise signals,
in order to fulfill symmetry require-
ments of CCITT's I.430 recommendat-
ion. Large common mode signals are
not tolerated by the input stage of the
MTC-20172 SIC. External series resis-
tors are needed for minimal impedan-
ce, see 5.3.3. Moreover, external
protection against foreign voltages is
needed (see appendix A).
5.3.2 Ternary S-bus Receiver
Polarity and Balanced
Operation
The ternary S-bus receiver is polarity
independent. It is fully balanced,
which means that it can be connected
to the balanced S-bus with a symmetri-
cal transformer, with a grounded
center tap at the S-bus side to better
reject longitudinal noise. The balan-
ced secondary is connected directly to
the MTC-20172 SIC with 2 series
resistors, as explained in 5.3.3.
The MTC-20172 SIC S-bus receiver is
backwards compatible with the unba-
lanced ones (e.g. MTC-2072 SIC).
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5.3.3 Ternary Receivers:
Impedance While not Powered.
When the MTC-20172 SIC is under
power, the balanced inputs are
capacitive loads on the bus. However,
in the TE (or LT-T) position, when the
bus is active but the MTC-20172 SIC
is not powered, a minimal input
impedance is required by the CCITT
I.430. With 1.2 V (peak) applied the
current will be less than 0.6 mA.
Part of this current is drawn by the S-
bus transformer with a parallel
impedance of minimally 2.5 k. The
MTC-20172 SIC input structures
present protection diodes to the power
supply and ground (VDD and VSS
pins). To guarantee a current below
0.6 mA external series resistors must
be put between the MTC-20172 SIC
receiver pins and the transformer.
Note that these resistors also serve as
input protection. Typically, 10 kis
needed in series (see appendix A).
5.3.4 Activity Detection:
When the device is in power-down
state, a Line Signal Detector is
enabled to detect the presence of
incoming data. No clock must be
present. The activated MTC-20172
SIC signals this via the GCI bus, see
6.2.
5.3.5 Sensitivity/AGC:
The receiver contains an AGC, which
adjusts the gain of the received signal
before synchronization, to optimize
the detection of the frame violations.
After frame synchronization, the AGC
slowly and continuously tracks the
height of the F bit at the optimized
sampling moment, to normalize the
height of the rest of the frame and to
improve the bit detection of the
remainder of the frame. The AGC
tracking is based on the comparison
of the received F bit signal with two
thresholds at 95 % and 105 % of the
reference level. The range between
the thresholds, where the AGC is
stable, is larger than worse case AGC
step to avoid continuous toggling of
the gain (i.e. hysteresis).
The AGC uses the height of the F bit at
the sampling moment to exclude the
pulse overshoots which can exist on
short passive buses, with reflections on
high-ohmic cables.
The AGC reference level is put at 85%
of the nominal pulse height, or -1.4 dB
relative to the nominal signal. Stronger
signals (above -1.4dB relative to
nominal) are not amplified. This is
necessary, so as to ignore signal
overshoots caused by multiple drivers
and by reflections on short buses,
which can mask a weaker driver at -
3.5 dB.
5.3.6 MTC-20172 SIC RX Signal
Dynamics and Detection at
TE/LT-T
At the TE/LT-T position, the signals are
generated by a single source, and
they are only distorted by reflections
on the S-bus in the short passive bus
situation. Those refections cause
overshoots, which affect the AGC
before synchronization is found.
However, after synchronization, the
slow AGC tracks the incoming signal
at the optimal sampling moment of the
F bit and the overshoots are ignored.
Signals above -1.4 dB relative to
nominal are not amplified by the
AGC. F/L bit detection is done at
33% of the nominal level. Detection
thresholds for all other bits are at an
optimal 42.5% of the nominal level,
which is the ideal relative level of 50
% for all signals below -1.4dB, until
the AGC gain saturates for signals
below -15 dB.
5.3.7 MTC-20172 SIC RX Signal
Dynamics at NT/LT-S
The incoming S-bus signals can be
stronger than the nominal signals at
the output of a single driver, because
multiple drivers can enhance the F-bit
up to 140%. The amplitude of the F-bit
is therefore not a reliable indicator for
the optimal detection levels of the
individual bits of B and D channels.
On the short passive bus, the F-bit at
around 140% of nominal can mask a
distant driver at -3.5dB, according to
CCITT I.430.
In the bus configuration, the ratio
between individual B-channel bits and
the F-bit ranges from 100% to 140%,
depending on the number of drivers,
with a worst case transmission cable
loss of 3.8 dB or signal loss of 5.5dB.
In the point-to-point case, F and B-
channel bits are equal, with losses
limited to 7.5 dB by CCITT I.430, but
accepted by MTC-20172 SIC up to
15dB.
5.3.8 MTC-20172 SIC RX
Detection Levels at NT/LT-S
The detection levels and AGC setting
is not influenced by the bus type
selected at the NT (fixed timing or
adaptive timing).
The presence of multiple drivers or a
mix of weaker and stronger drivers is
not recognized by the MTC-20172
SIC. However, the detection is
improved by not applying any AGC
when the F-bit is stronger that -1.4 dB
relative to nominal, and by selecting 3
different absolute detection levels after
the AGC stage, in function of the
AGC gain.
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5.3.9 Filtering:
The receiver filters the signal with a
continuous-time filter. This is a first
order filter, which is tuned to fix its 3
dB point at 192 kHz ±10 %. The
delay of this filter is taken into account
for the advance of the transmitter bit
clock (TE/LT-T), see 5.3.12.3, or for
the position of the fixed sampling
moment on the short passive bus
(NT/LT-S, fixed timing), see 5.3.10.
5.3.10 RX Frame Sync and Bit-
sampling In NT/LT-S Short Bus
Mode.
The bit-sampling moment is fixed, and
coupled with the TX bit clock, which in
turn is derived from the crystal clock,
and locked to the GCI frame. The RX
bit counters (giving the position of the
uplink bits in the frame) are also
locked to the downlink/TX bit counter.
Uplink data are 2 counts late.
The fixed bit-sampling moment is
advanced 5 periods of the 7 MHz
clock, before the edges of the SIC
transmit data stream. The advance is
needed to allow an advance of 7%
(or 3 periods) of the uplink data,
allowed according to the CCITT to be
sent by TE at zero distance, combined
with a 1 period jump of the downlink
data clock derived from the crystal.
This relationship is valid on the S-bus
itself. Inside the SIC, the actual bit
sampling is delayed to account for the
nominal delay of the external transfor-
mer, the internal filters and driver
delays. The total delay of the external
devices is estimated at 100 ns, the
internal delay is implementation
related (see also 5.3.9).
Moreover, the sampling can be
delayed extra by 5 periods of the 7
MHz clock via the XTR4 pin, and also
via internal register programming;
see 5.4.3.
The frame synchronization knows the
F position, and applies the rules of
5.1.9 (i.e. without oversampling).
The NT/LT-S in fixed bus mode can be
forced to loop the S-bus signals
internally. Then SIC applies adaptive
timing, to maximally test the device’s
functionality.
5.3.11 Frame Synchronization
Details in Adaptive Timing.
The general synchronization rules are
given under 5.1.8. They apply to
NT/LT/TE.
During synchronization, the device
oversamples the incoming bits with a
fixed threshold, which is at 33 % of the
nominal pulse height, with AGC active.
5.3.11.1 First Violation Detection
The oversampling is done at the 7
Mhz master clock, or a factor 40. A
simple voting technique is used to
detect a violation: The detector output
increments a counter as long as the
detected bits are marks of the same
polarity or zeros. When a polarity
change of the marks is seen, the coun-
ter is cleared. Whenever a sequence
of more than 50 oversampled marks
of the same polarity are seen, the
receiver decides that a violation came
in. The number 50 is not so large so
as to allow synchronization on signals
with flat edges.
After finding a single violation, the
oversampling looks for the mark-to-
zero and the subsequent zero-to-
opposite-mark transition, which it then
uses to estimate the actual F/L
crossing; see 5.3.12 below.
5.3.11.2 Violation Validation
During the hunt for frame synchroniza-
tion, the F/L transition forces the RX bit
sampling clock and bit counter to a
deterministic state, which is optimal;
see 5.3.12 below.
The RX part now hunts for a next
violation. In fact, the next mark must
be a violation. This violation (polarity
should be opposite, but this is
ignored) must arrive before the
counter indicates 14 received bits. If
the second violation is found before
14 received bits, the F/L must be
validated for 2 more consecutive
frames.
In all following frames, the F/L
transition is oversampled to lock the
RX bit sampling clocks with DPLL
movements of 1 period of 7 MHz.
If the F/L validation is not correct
during the 2 subsequent frames,
MTC-20172 SIC restarts the hunt of
5.3.11.1.
5.3.12 RX Bit-Synchronization
in TE/LT-T and NT/LT-S Adaptive
Bus
Bit-Synchronization is done only by
detection of the F-L zero crossing. This
is optimal for short buses and extended
buses, where multiple signal sources
are present, each with an independent
bit timing. Only the F/L is a "stable"
combination of all electrical drivers on
the bus. For long point-to-point links,
the same technique is used.
Each time the bit counters indicate the
reception of F/L, the RX part
oversamples the transition at 7 MHz.
The F/L crossing is used for
several purposes:
1) It gives an immediate estimate of
the RX data optimal sampling
moment, after a first violation is
found, via oversampling.
(explained in 5.3.12.1)
2) It indicates how to correct the RX
192 kHz sampling clock each
frame by one 7 MHz period; (DPLL
action in adaptive RX sampling).
(explained in 5.3.12.2)
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3) It determines the reference point for
the transmit clock in TE/LT-T mode.
(explained in 5.3.12.3 and related
to 5.2.5.2)
The "F-L zero crossing" is not detected.
MTC-20172 SIC detects the transition
mark-zero (instant t1) and the
subsequent zero-opposite-mark (instant
t2). During the F/L bits, the device
oversamples the incoming signal with
a fixed threshold, which is ALWAYS
at 33 % of the nominal pulse height.
AGC is active, see above.
In between t1 and t2, the RX part
counts "Y", the number of zeros, igno-
ring possible marks. The zero count Y
is less than the t2 - t1, because noise
could force marks to be seen by the
receiver during the interval.
The number "Y" of intermediate zeros
is used to estimate the slope of the
arriving signal, to predict the edge of
the F/L transition. Y is limited to 15,
which corresponds to a first order time
constant of 2 µs for the S-bus data,
filtered by the MTC-20172 SIC input
filter. This is 2.5 times slower than the
worst case point-to-point signal as
specified in CCITT I.430 Figure 6.
Note that Y could be larger than 15 if
the zero crossing is sought on a mark
which is followed by a zero bit, i.e.
when the violation is not the F bit
followed by L.
5.3.12.1 Immediate Bit
Synchronization at Instant T2
When the receiver is not synchroni-
zed, the receiver is oversampling and
hunts for violations as explained under
5.3.11.1.
The F/L crossing is found at instant t2,
and the 192 kHz bit clock and the
1536 kHz receiver clock are preset to
predict an optimal sampling moment.
The data edge is estimated at instant
(t2 - 2.00*Y).
For all modes (NT/LT-S and TE/LT-T)
the optimal sampling precedes the
theoretical edge by 8 periods of the 7
MHz clock. The advance is needed to
allow a jitter of 7% (15% or 6 periods
of 7 MHz) of the data, allowed
according to the CCITT to be sent by
any TE, combined with a 1 period
DPLL correction needed at the NT/LT-S
to correct for its own crystal.
Similar data jitter is also present at the
TE when for example a 200 kHz
interference signal, with amplitude
100 mVpp (peak to peak) is applied,
as specified in CCITT I.430 8.6.2.1.
5.3.12.2 Continuous Bit
Synchronization at Each F/L
Crossing.
Once the receiver is synchronized on
the data, the F/L edge is used on each
frame to validate the sampling
moment. The oversampling clock is
used in the F/L window to validate the
zero crossing.
At instant t2 (zero to opposite mark
transition) the state of the counter
generating the 192 kHz clock from the
7 MHz is compared with the optimal
value, which should be loaded for an
immediate bit synchronization as
explained in the preceding section. If
the difference (in nr. of periods of 7
MHz) is -1, 0, or 1, the counter is not
changed, to provide hysteresis. If the
difference is larger, the counters are
adjusted with only 1 1, to limit the
DPLL reaction.
In this manner, the sampling moment
is adjusted with one 7 MHz period,
every 250 µs. At the TE this allows a
maximum frequency error of the
crystal of 500ppm.
5.3.12.3 Optimal TX Bit Clock
Derivation (ONLY at the TE/LT-T)
Once the receiver has reached
synchronization, as explained in the
previous paragraphs, the transmitter at
the TE/LT-T can start sending INFO3.
When starting to transmit, the transmit
bit clock is forced at once to an
optimal initial state, based on the
downlink F/L edge. On each
subsequent downlink F/L the transmit
clock will be adjusted one period of
the 7 MHz clock.
In the MTC-20172 SIC, the theoretical
zero crossing is derived from the t2
and Y values, using the following
formula, which incorporates the effect
of the first order RX filter.
zero crossing time = t2 - 0.75 * Y - 5
On each subsequent received
downlink frame, the DPLL does the
following comparison: at instant t2 the
TX clock counter should contain 0.75
* Y - 5. If the difference is within a
dead zone of 1 1 period of 7 MHz
around the optimal point the TX clock
is not adjusted. Otherwise the clock is
adjusted, but the maximal TX clock
correction per frame is limited to 1 1
period of the 7 MHz. (Internally, the
timing reference is corrected for other
internal implementation delays besides
the RX filter).
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5.4 Timing Relation
Between RX and TX
on the S-Bus
The timing relation between RX and TX
on the S-bus depends on the MTC-
20172 SIC mode. Moreover, it can
be trimmed, as described in 5.4.3.
5.4.1 S-bus Transmitter Versus
Receiver Delay in TE/LT-T Mode
The CCITT imposes exactly 2 S-bus
symbols, with a margin of +7% to -15%
on the S-bus reference point. The
downlink F/L framing signal is used as
reference timing. Delays of the normal
external devices (transformer) and
internal MTC-20172 SIC filters are taken
into account, during implementation, to
advance the TX frame relative to the
received F-L transition. In some
applications, the external circuits add
delay in the receiver path. For that
reason the SIC device can force an extra
time advance of the TX frame via the
XTR4 strap.
5.4.2 S-bus Receiver Versus
Transmitter Delay in NT/LT-S
Mode
The Delay between transmitted and
received frames at NT/LT-S is 2 bits
plus the round-trip-delay across the S-
interface, in normal operation. Worst
case delay between downlink frames
and uplink frames is 42 µs (see CCITT)
or 8 bits. Longer delays cause
problems for correct transmission of the
E-channel bits, see 5.6. In loopback
mode, the delay is zero.
The receiver in NT mode is designed
to accept any delay while in adaptive
sampling mode. This is convenient
when looping the S-bus signals. E-
channel operation is only correct if the
delay is 0 to 8 bits.
5.4.3 Delay Trimming Via
XTR4 Pin
The XTR4 or X4 pin can be used at
NT/LT-S with fixed timing and at
TE/LT-T.
In some applications the XTR4 pin can
be used to trim for the delay of an
external filter circuit.
The delay trimming has different
effects:
In NT/LT-S with fixed timing on short
bus, XTR4 at 0 delays the sampling
moment with 5 periods of the 7 MHz
clock, or 650ns. In the adaptive
timing, no effect is seen.
In TE/LT-T mode XTR4 at 0 advances
the normal transmit instant (2 symbols
relative to the received frame) with 5
periods of the 7 MHz clock, or 650
ns. The delay is reduced.
5.4.4 More Delay Trimming.
The delay trimming can also be
controlled via the GCI M-channel,
adding 650 ns to the effect of the XTR4
pin. See 7.7.3 on internal registers.
5.5 Frame Relation
Between GCI and
S-Interface
In all modes of the MTC-20172 SIC
except the LT-T mode, there is a strict
relation between the S-bus frame and
the GCI bus frames.
5.5.1 S-bus Transmitter Bit and
Frame Clock NT/LT-S
If the MTC-20172 SIC is in the
Network position, the 192 kHz S-bus
bit clock is derived from the crystal
clock, which is locked to the 8 kHz
frame of the GCI bus.
The leading edge of the F-bit starts the
frame on the S-bus. The DPLL inside
MTC-20172 SIC forces this F-bit edge
in a fixed range relative to the frame
signal of the GCI bus.
Phase Relation Rule (NT/LT-S):
The F-bit start is situated in a 520 ns
zone, starting with the edge between
bit0 and bit1 on the GCI bus. The
uncertainty is caused by the DPLL
actions which will correct the 192 kHz
S-bus clock in steps of 130 ns, i.e. one
7.6 MHz period.
Figure 5.5 shows the timing relation
between the S-bus frames and the GCI
bus for DCLK at 512 kHz (NT).
This phase relation optimizes the total
roundtrip delay on the S-bus for each
B-channel, if the GCI clock is 512 kHz.
The delay of the NT with S-bus looped
is only 125 µs for both B-channels at
the GCI side. (This is the minimum).
For GCI clock speeds higher than 512
kHz, the round-trip delay can not be
optimized for both B1 and B2 channel
simultaneously. At least one B-channel
has a 250 µs delay.
For simplicity, the S-bus frame and the
GCI frame will keep the same phase
relation independent of the used GCI
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channel and for all GCI clock speeds.
In this way, the B-channel roundtrip
delay over the looped S-bus is
maximally 250 µs.
The S-bus frame is locked to the GCI
frame, with of course two random
locking positions possible at a 125 µs
distance. This forces all D-channels
and E-channels of a group of SICs on
a LT-S GCI bus to coincide. This allow
the use of a common echo-bus to link
multiple D-channels in a star
configuration to a single HDLC
controller at the LT-S side, see 5.6.
5.5.2 S-bus Transmitter Clock
and Frame in TE Mode
In the TE position, the MTC-20172 SIC
will lock on the 192 kbit/s received
AMI data. The frame transmitted at the
terminal side is delayed by two bits
with respect to the received frame (see
5.4.1), adjustable according to 5.4.3.
The frame relation between the linked
downlink and uplink S-bus frames and
the local GCI bus of the TE is also
fixed. The relationship is deterministic:
it has minimal B-channel delay for
both possible clock speeds of the GCI
bus (i.e. 512 or 1536 kHz).
Phase Relation Rule (TE):
The downlink frame starts with the F-
bit, which is followed by a balance bit
L. The MTC-20172 SIC will force the
leading edge of bit 0 of the B2
channel on the GCI bus to coincide
with the internal sampling moment of
the L-bit. The edge of the 8 kHz GCI
frame signal precedes this instant by
exactly 16 clock periods of the DCLK
clock (i.e. 512 or 1536 kHz).
Figure 5.6 shows this for the 512 kHz
case. Round-trip delay with GCI data
looped is 125 µs.
Note that before the S-bus receiver is
locked to the uplink device, the GCI
clock and frame are asynchronous.
When synchronization is acquired, the
MTC-20172 SIC will put the GCI
frame in the optimal position (single
jump). See also 4.10.2.
TE-mode exception: The clock relation
is not applicable in TE-mode when the
transmitter signal is looped back to the
receiver. During this non-transparent
analog loop, the MTC-20172 SIC
uses its local crystal as master clock,
and locks the GCI clock to the crystal.
Note also that activation via the S-bus
is possible during the loop mode.
5.5.3 Transmitter Clock and
Frame in LT-T Mode
In the LT-T position, the MTC-20172
SIC will lock to the 192 kbit/s
received AMI data, as in the TE case.
The frame transmitted at terminal-side
is delayed for a period of two bits
with respect to the received frame.
This is deterministic, see 5.4.1,
adjustable according to 5.4.3.
The main difference with the TE case
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Fig. 5.5 : GCI S-bus Phase Relation TE Mode, RDY & ECHO pin
is the absence of synchronization of
the S-bus and GCI bus. In LT-T mode
the both the GCI and S-bus clock and
frame signals are received. The MTC-
20172 SIC must accept any phase
relation between both frames. After
GCI activation and S-bus
synchronization, it presets the pointers
in the RAM buffer between between
both interfaces to allow a wander of
18 µs.
If, in spite of the 18 µs distance, the
pointers in the RAM buffer are
crossing over, the RAM pointers are
shifted with 125 µs. This causes the
repetition or deletion of a B-channel
byte and of 2 bits on the HDLC D-
channel.
LT-T-mode exception: The relation
between transmitted bits and received
bits at the S-bus is not applicable in LT-
T-mode when the transmitter signal is
looped back to the receiver. During
this non-transparent analog loop, the
MTC-20172 SIC uses the GCI clock
as master clock, and locks its crystal to
the GCI timing. (This behaviour is
more NT/LT-S like, except that the
loop is not transparent on the bus!).
Note also that activation via the S-bus
is possible during the loop mode.
5.6 E-Channel Genera-
tion in NT/LT-S
At the NT/LT-S, the MTC-20172 SIC
mirrors the uplink D-bits in the down-
link E-channel. The purpose of the E-
channel is to control the D-channel
access from multiple TEs on the S-bus.
In INFO2, the E-bits are zero; in
INFO4, the E-channel mirrors the
preceding D-channel bit received in
the S-bus receiver.
5.6.1 E-Channel Generation In
NT in STAR Configuration
In the STAR configuration, two or
more MTC-20172 SIC devices drive
separate physical S-buses, which are
logically combined.
This STAR configuration allows the
construction of a special NT1 where
multiple point-to-point S-buses are tied
to one U0-line, working logically as a
single short passive bus.
The STAR configuration requires a
logical combination of D and E-
channels, and of the C/I and M-
channels at the NT/LT-S. B-channels
remain point-to-point links, assigned
via the LAPD.
The MTC-20172 SIC restricts the STAR
configuration to the D-channel, using a
special Echo bus, explained in 5.6.3.
The C/I channels of each MTC-20172
SIC are not combined. The C/I
channel considerations are explained
in 6.5.6.
5.6.2 E-Channel Generation In
LT-S For HDLC Pooling
Theoretically, the same STAR
configuration is possible in the LT-S
position also. However, if the logical
combination of S-buses is limited to
the D-channel, it becomes possible to
handle multiple S-buses with a limited
pool of HDLC transceivers, without
restricting B-channel connections, and
without any C/I channel problems.
Each MTC-20172 SIC has its own
GCI channel. The D-channels are
merged via a special Echo bus,
explained in 5.6.3. As long as MTC-
20172 SIC devices are tied to the
Echo bus they can be handled by a
single HDLC D-channel device. All
individual D-channels contain the
same LAPD signals. The pooled HDLC
device must be connected to only one
of them. If the load on a shared D-
channel is too large, individual D-
channels can be disconnected from
the shared HDLC receiver. Each MTC-
20172 SIC can be programmed via
an enable pin or via the M-channel to
leave the Echo bus.
5.6.3 E-Channel Generation:
Operational
Without STAR, the E bit is simply the
echo of the downlink D-bit. There is an
exception in the extended Mode,
when the TIC protocol is used, see
5.8, but the TIC protocol is NOT
implemented.
The SICs in STAR or HDLC-pooling
configuration use a common bus line
to combine all accesses to the uplink
D-channel. It is called D-channel Echo
(DE) bus in Basic Mode, and the Com-
mon Echo Bit (CEB) bus in extended
Mode. The bus pin has an internal 50
kpull-up resistor (pin XTR0 in NT
mode, pin AUX4 in LT-S mode). Each
MTC-20172 SIC can pull the bus low
with an open drain output.
When a group of SICs is tied to a DE/
CEB bus, each SIC can individually
participate or not. Participating SICs
drive the received D-channel bits via
the open drain output, and sense the
common E-bit. The common E-bit is
also the D-channel bit which is sent on
the GCI channel. Non-participating
SICs do not pull the bus low and
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Fig. 5.6 : GCI S-bus Phase Relation NT/LT-S Mode, DE/CEB timing
5.7 D-Channel Access
in TE/LT-T
In the uplink direction, the D-channel
is organized in a multipoint manner
on the S-bus.
To allow only one TE on the D-
channel, a collision detection and a
strictly fair access protocol is defined
by the CCITT I.430. To detect the
availability and collision at the TE, the
E-bit echo channel is used. The
downlink E-channel contains the
reflection of actual uplink D-bits which
are seen at the NT/LT-S, see 5.6.
When an electrical collision happens
on the S-bus, the binary zero wins.
The messages sent on the D-channel
are HDLC messages, containing a
start flag, message bodies and end
flag. In between the messages the
channel returns to idle (all binary
ones). The idle on the D-channel
allows the different TEs to detect the
availability of the D-channel. The TEs
do not monitor idle on the uplink D-
channel directly, but monitor this via
the E-channel.
When the TEs see the idle on the E-
channel they can start a message. The
TE which start first gains the access,
because the start flag begins with a
zero. When many TEs start a message
simultaneously at the same bit posi-
tion, the flags will coincide. However,
the message body will differ some-
where. The collision detection is based
on E-channel observation. The TE
which sends D = binary one which is
overwritten by a zero on the S-bus,
loses the access, because the E-chan-
nel reflects the zero. The TE which
detects a collision releases the D-chan-
nel by sending idle on the bus. The TE
which won the collision, continues
without even knowing it occurred.
After a TE has transmitted a complete
message, or lost the D-channel in a
collision, it must detect a number of
idle bits X before it can start another
transmission. The number X is defined
for 2 priority classes: X=8 and X=10.
When a TE has successfully
transmitted a message it increases X
by 1 (to 9 or 11). If X is at 9 (or 11)
and this exact number of ones for an
idle is seen on the bus, then it resets
the X to 8 or 10.
ignore the content.
Participation on the DE/CEB bus can
be forced via a pin (DEX) and via an
internal register bit. The participation
is a logical function of the DEX pin
(see 4.11 and 4.12) and the DEX bits
(control via the M-channel, see 7.7.3).
Implementation issue:
Note that each individual MTC-20172
SIC tied to the DE/CEB bus must work
with the same GCI frame indication,
but not necessarily the same GCI
channel. Each MTC-20172 SIC drives
the S-bus with frames strictly synchroni-
zed to the GCI interface frame, see
5.5.1, and Figure 5.5.
This means that driving and sensing
the DE/CEB bus can be done in a
distributed way. Each MTC-20172
SIC drives the DE/CEB bus when the
uplink D-bit is sampled, and senses the
DE/CEB bus when E-bit must leave,
without possible discrepancy in each
E-channel. Note that DE/CEB could
work incorrectly when the uplink sig-
nals have a delay of zero bits, i.e. in
loop condition. The timing diagram is
included in Figure 5.5.
HDLC message properties:
The HDLC flag is 01111110 in
binary, or 7E hex. The message
bodies never look like idle or flags,
because a bit stuffing mechanism
forces extra zeros when 5 consecutive
ones are seen, see CCITT I.430. In
some cases the message body is not
terminated correctly with a flag but
with idle; this is an abort. When
aborting a message, the TE must
release the D-channel also
5.7.1 D-Channel Access
Working Principles for the MTC-
20172 SIC
The TE/LT-T access on the D-channel is
the combined operation of the MTC-
20172 SIC working together with an
intelligent HDLC device. The D-channel
coming from the HDLC device is not
transparently transmitted from GCI bus
to the S-bus. Inside MTC-20172 SIC,
there is a D-channel Access Controller
(D-AC), which limits the access
according to the S-bus rules.
The D-AC knows about the general
principles of the HDLC LAPD channel
and of the echo channel. It must
recognize the idle via the E-channel, it
must know about the priority classes
when trying to access, it must track the
HDLC messages of its local HDLC
transmitter: It recognizes the (single)
start flag of a message and the end
flag or abort of the message. When it
sends a message it must recognize the
collision of the message on the S-bus.
5.7.2 The D-Channel Access
Controller (D-AC) - Functional
description
The D-AC can only handle one priority
class simultaneously. The priority is
indicated via the C/I nibble in the
GCI B1*-channel, see 6.5.10.
The D-AC can be in the READY or
BUSY state. The D-AC changes states
at each observation of the (downlink)
E-channel. When it is in the READY
state, it allows the GCI D-channel
transparently on the S-bus. When it is
BUSY it forces idle on the S-bus. The
detailed state diagram described in
Figure 5.7, with a number of control
variables:
- The variable C: the count of
consecutive ones on the E-channel;
- The variable P: indicates the priority
class (8 or 10);
- The variable R: 0 or 1, indicates the
priority reduction; simply added to
P, changing priority to 9 or 11;
- The variable V: indicates a violation
between D and E when 1.
The D-AC can only go from BUSY to
READY when the E-channel contains a
number of idle bits equal to or larger
than X, the priority class. This is when
C= P + R. The condition C>= P + R is
used, to allow changes in P.
The D-AC goes from READY to BUSY
when:
1) a violation is seen, (from states
RDY1, RDY2, RDY3 to BUSY);
2) OR the start flag + message body,
is eventually followed by an end
flag; message can be empty;
3) OR the start flag + message body,
is eventually aborted (forced to idle
without end flag); message can be
empty;
4) OR a starting flag degenerates to
idle;
5) OR a message without correct
starting flag is followed by an end
flag + idle or is aborted;
The D-AC will allow D-bits
transparently on the S-bus when it is in
the RDY1 to RDY4 states. The RDY4
state is added to the Basic Mode state
diagram, to allow the last zero of the
tail flag to leave. The MTC-20172 SIC
has only a limited control on the
content of the D-channel after it goes
to the READY state. See 5.7.7.
The BUSY2 state is added to send an
anticipated READY via the RDY pin
and via the GCI bus, see 5.7.3 and
5.7.4.
The Variables and how they
Change :
Variable R goes to 1 when a
successful end flag is transmitted or
when a message is aborted, i.e. in the
RDY4 state. The variable R goes to 0
when C>= P + R, i.e. in the RDY1
state. CCITT I.430 states: The priority
count X (=P+R) can be reduced, i.e. R
:= 0, when the priority count X is at P
+ 1 (9 or 11) and this exact number
of ones for an idle is seen on the bus.
Count C is updated for each received
E-bit. In the RDY4 state, C will be at 0,
because then the last (zero) bit of the
end flag is seen. We force C = 0 in
the RDY4. This happens when the local
HDLC message was aborted, and it
keeps the local HDLC transmitter from
restarting a new message too soon.
Variable V is the Violation detection.
To change states, the D-access
controller compares the D-channel bits
with the E-channel bits. This
comparison is done bit by bit. The
variable V is the EXOR of the E-bit and
the D-channel bit sent on the S-bus.
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Fig. 5.7 : State Diagram of
D-Channel Access Procedure
Normally, a violation is E=0 and D=1,
however the opposite case is also
considered a violation. This stops the
message when a bit-error is seen.
Variable P contains the priority class,
8 or 10. This variable can change via
the command interface, see 6.5.10.
When P is changed in the RDYi states,
the ongoing transmission will not be
affected.
5.7.3 READY Signal
The external HDLC controller can
monitor the READY/BUSY via a pin
and via a bit on the GCI bus, in the TE
and the LT-T modes.
The RDY pin is available in the TE and
the LT-T position in Basic Mode and in
extended Mode, see 4.11 and 4.12.
The polarity is normal. RDY = 1 means
D-channel available. RDY = 0 means
D-channel NOT available.
The MTC-20172 SIC has a BUSY bit
in the GCI M-channel at the 5th
position (numbering 1 to 8), in TE and
LT-T position, for both modes. The
polarity is normal. BUSY = 1 means D-
channel NOT available. BUSY = 0
means
D-channel available.
The MTC-20172 SIC in the extended
TE mode has an extra RDY bit in the
B*-channel of the GCI channel 2,
position 3 (numbering 1 to 8). The
normal GCI information is in the GCI
channel 0. The name RDY is
confusing, because the polarity of this
RDY bit is INVERTED. RDY = 0 means
D-channel available. RDY = 1 means
D-channel NOT available.
The MTC-20172 SIC always offers
both the BUSY bit in the M-channel
and the RDY pin.
5.7.4 Anticipation and LAPD
Fairness
Anticipation
The RDY pin and the RDY bit must anti-
cipate the READY state, because the
uplink D-channel is sent with two bits
grouped, because the E-channel has
an extra roundtrip delay, and because
the RDY pin and the BUSY signal are
sampled at a fixed position in the 8
kHz GCI frame.
The BUSY2 state anticipates the RDY
pin and bit indication.
Lapd Fairness
In spite of the anticipation of the RDY
signals, the LAPD fairness is not opti-
mal. Indeed, the relation between the
MTC-20172 SIC and the HDLC trans-
mitter via the GCI bus limits the reac-
tion time. Even in the best situation,
the uplink messages will be one bit
late in 50 % of the time. Giving more
anticipation is impossible, because
then it could happen that the ready
indication arrives too soon at the
HDLC controller. The opening flag
would then be mutilated, which causes
useless retransmission delays and
even deadlock situations.
In the LT-T position, the fairness is
worse, because the delay of the D-
channel is larger, caused by the asyn-
chronism between the GCI bus and
the S-bus. Luckily, in LT-T mode, the
MTC-20172 SIC is normally the only
TE on the T-bus, and fairness is not an
issue.
Fairness Enforced ?
If the HDLC controller wants a fair
access in TE or LT-T mode against
some other terminal on the S/T-bus, it
can force the D-channel in all zero
state. The D-AC will dump the zeros in
the D-channel, which blocks the access
of all other TEs. The leading zeros can
be followed by a normal start flag +
message + tail flag and idle. Also see
5.7.7.
Note that the priority change X to X+1
will still allow all other terminals an
access on the D-channel.
5.7.5 RDY Pin and Bit
Operation in Basic Modes;
Anticipation in the Basic TE mode is 2
bits.
Anticipation in the Basic LT-T mode is
1 bit.
Timing (see Figure 5.6)
5.7.6 Timing and Operation in
extended Modes;
Anticipation in the TE and LT-T mode is
1 bit.
Timing (see Figure 5.6)
In the extended mode of the MTC-
20172 SIC, the RDY pin and the
BUSY bit in the M-channel change
simultaneously.
5.7.7 Illegal Messages from the
HDLC:
Multiple Leading Flags:
MTC-20172 SIC will not handle
messages with too many leading
flags. It will consider any second flag
a terminating one and go to BUSY.
Messages preceded with non-
idle preceding the start flag.
If the start flag is not preceded by a
normal idle but by some header
containing zeros, different from a flag
or idle, the D-AC remains in the RDY2
sub-state. It will wait for the start flag +
message + tail. It was decided to
allow this incorrect behaviour of the
HDLC transmitter to avoid some
problems in the LT-T situation, see
5.7.4 above.
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Messages started without a start
flag.
The D-AC does not block messages
without a legal start flag from the local
HDLC transmitter.
When the HDLC is not synchronized
with the READY signal, it could
happen that the D-AC opens the D-
channel to the HDLC transmitter while
it is not sending idle. Then a message
without opening flag is sent on the D-
channel of the S-bus.
The D-AC can not detect this behaviour.
The D-AC reaches the different ready
states. It goes only to BUSY when the
end flag arrives followed by idle, or if
the message is aborted (forced to idle
without end flag). The HDLC receiver in
the NT position will normally ignore the
message. It will only react on the end
flag followed by the idle.
5.7.8 E-Channel To External-
HDLC Device at TE Position.
The D-channel access can also be
controlled outside the MTC-20172
SIC, by supplying the E-channel to the
external HDLC device.
In Basic Mode, the E-channel is put on
the ECHO pin, see 4.11 and 4.12.
The ECHO pin contains the downlink
E-bits synchronized with the GCI D-
bits. All other bits are at 1. Timing as
in Figure 5.6.
In the extended (GCI) TE mode, the
actual E-channel is not available on a
separate pin, but present on the GCI
bus. The normal GCI information is in
the GCI channel 0. The extra E bits
are put in B*-channel of the GCI
channel 2, position 1 and 2,
numbering from 1 to 8. Timing in
Figure 5.6. (NOTE: The 3rd bit is the
RDY indication).
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5.8 D-Channel Access
in NT/LT-S: TIC
Protocol
This feature is NOT included in the
MTC-20172 SIC.
If necessary an intelligent HDLC
device can use the DE/CEB bus to
monitor the E-bits and to drive the
GCI D-channel, see 5.6. Only the 16
kHz clock must be provided
externally, synchronized with the GCI
framing.
5.9 Multiframing;
S and Q Channel
Functions
The MTC-20172 SIC supports
multiframing according to I.430.
The MTC-20172 SIC can transmit a
Q-channel at 800 bit/s uplink,
synchronized with a multiframing
indication. In the downlink direction,
the MTC-20172 SIC can send a
multiframe indication and the S-
channel at 800 bit/s.
The S and Q bits can be accessed via
the M-channel, see 7.5. During
system reset condition, the internal
MTC-20172 SIC S and Q-bit registers
are set to logical '0' at the NT/LT-S
and set to logical '1' at the TE/LT-T.
5.9.1 Compatibility With the
MTC-2072 SIC
In the MTC-2072 SIC, a bit called “E-
bit” in the B1* channels was used to
enable and synchronize the
multiframing. This operation is not
supported anymore. It was not
supported by any other component.
5.9.2 Multiframing Enabling
The enabling of multiframing is
the OR function of 3 inputs:
1) a PIN (MFD),
2) a register bit, and
3) a special GCI framing.
1) In the NT modes (Basic and
extended modes) there is a MFD
MultiFrame Disable pin, with an
internal weak pull-up, see 4.12.
2) In ALL modes, multiframing can be
enabled via the M-channel on the
GCI bus. At RESET the
multiframing is disabled.
3) In ALL modes, except in the inverted
mode multiframing can be enabled
via the width modulation of the
GCI frame signal, see next section.
5.9.3 Functional Behaviour at
The NT/LT-S
When multiframing is disabled, the
MTC-20172 SIC will send the FA and
the M bits and also the S-channel as
binary zero, in downlink direction.
When multiframing is active, the
MTC-20172 SIC transceiver will send
FA='1' as "Q-frame identifier" in
every fifth S-bus frame, and M='1' as
multiframe identifier in every 20th S-
bus frame (5 ms), as required in the
CCITT I.430. The coding of the
corresponding N-bit remains always
N = .NOT. FA.
The S-channel is a 4 kbit/s channel,
transmitted in frames of 20 bits,
subdivided in 5 groups of 4 bits, for i
= 1 to 5, Si1, Si2, Si3, Si4. Only the
S1j bits can be accessed, or 400
bit/s. The other S bits are forced to 0.
See TABLE 5.1.
Synchronous with the M=1, FA=1, the
S11 bit is sent. The S-bits are taken
from the S registers, writable via the
M-channel. In the uplink direction, the
Q1, Q2, Q3, Q4 bits are found at the
FA position of the received S-bus
frames and stored in the Q register,
accessible via the M-channel.
When the width of the frame pulse is
reduced to one clock period of the
data clock, the MTC-20172 SIC will
enable multiframing. The width
modulation must be done with a
cadence of once per 5 ms, and the
MTC-20172 SIC will synchronize the
multiframe start (S and M bits at
binary ONE) with this event. Frame
width modulation is impossible in the
inverted mode, because the frame
pulse is always 1 clock period long.
5.9.4 Functional Behaviour at
TE/LT-T Side
If the MTC-20172 SIC has
multiframing disabled at the TE/LT-T
position, it sends an uplink frame
having FA = 1, in response to each
downlink frame with FA = 1.
If the MTC-20172 SIC has
multiframing enabled at the TE/LT-T
position it tries to synchronize. As long
as MTC-20172 SIC is not
synchronized, it sends an uplink frame
having
FA = 1, in response to each downlink
frame with FA = 1.
Synchronization at the TE/LT-T: When
the MTC-20172 SIC sees M = 1, and
FA = 1 in a received S-bus frame,
followed by a complete 5 ms
multiframe with the correct values for
M and FA, then it assumes multiframe
synchronization. See TABLE 5.1, or
CCITT TABLE 7/I.430. As soon as one
value of FA or M is incorrect,
synchronization is lost.
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Table 5.1 : Multiframing Sequence
(with i = 2, 3, 4 or 5)
frame number FA downl. FA uplink M downl. S downl.
1 ONE Q1 ONE S11
2 - 5 ZERO ZERO ZERO Si1 = ZERO
6 ONE Q2 ZERO S12
7 - 10 ZERO ZERO ZERO Si2 = ZERO
11 ONE Q3 ZERO S13
12 - 15 ZERO ZERO ZERO Si3 = ZERO
16 ONE Q4 ZERO S14
17 - 20 ZERO ZERO ZERO Si4 = ZERO
5.10 BER PIN
The BER pin signals errors in the RX
data, when synchronization is
reached. If too many errors force the
MTC-20172 SIC out-of-sync, it
indicates this via the C/I channel.
BER = Bit Error Rate: each excessive
violation seen during the S-bus frame
between position 14 and 48
indicates a link transmission problem,
except in uplink frames during
multiframing (see 5.1.7). Each error
forces this BER output low for one S-
bus bit period. All BER outputs can be
tied to a single bus.
Once it is synchronized, the MTC-
20172 SIC starts transmitting the Q
channel in the next 5ms multiframe.
The Qi bits positions are shown in
TABLE 5.1, or CCITT TABLE 7/I.430.
5.9.5 Automatic S and Q Bit
Interpretation
Automatic power loss indication is not
implemented in MTC-20172 SIC.
5.9.6 Multiframing and
S-bus Synchronization
Multiframing affects the S-bus
synchronization, see 5.1.7.
6.2 The Physical
Organization of the
GCI bus
The bus has a clock and frame signal as
timing, and two data lines, one for each
direction.
The actual timing and speed of these
4 signals exists in several flavors and
variants. The MTC-20172 SIC
provides all the different variants of
the prevailing standards :
See TABLE 4.1:
- V* master mode, with clock at 512
kHz;
- V* slave mode, defined at 4096 kHz,
but accepting any CGI clock;
- Inverted mode at 512 kHz, clock inv.,
frame neg. & advanced;
- Inverted MUX mode at 4096 kHz,
clock inv., frame neg. & advanced;
- CGI master mode, with clock at 1536
kHz;
- CGI slave mode, clock recognition,
512 kHz - 8192 kHz.
The clock, frame and data relation is
shown in Figure 6.1; the timing and
electrical details in chapter 9.
6.2.1 Clock and Frame Signals
(see Figure 6.1)
In the TE mode, the clock and frame are
generated by the MTC-20172 SIC.
Here, the timing is slaved to the S-bus
and the network.
In the LT-T, the LT-S or the NT mode, the
MTC-20172 SIC receives the GCI
timing. In the LT-T the MTC-20172 SIC
must handle slip between the GCI timing
and the received S-bus clock.
6.1 The GCI Interface
At the digital control interface, the MTC-
20172 SIC is connected via a
bidirectional serial interface, a digital
bus called the General Circuit Interface
(GCI). Data (in B+D channels) and
control information are passed on a
256 kbit/s channel of the GCI bus. In
PABX systems, many SICs may be
connected to a single multipoint bus. In
this case, there is a "burst"
transmission. The MTC-20172 SIC
adapts its speed automatically to the
available speed on the bus. Moreover,
the MTC-20172 SIC can use one of 8
consecutive GCI channels, numbered 0
to 7. The maximal speed of the bus is
4096 kbit/s.
The description of the GCI standard is
also available as a separate document.
6.1.1 General Content of the GCI
Bus For MTC-20172 SIC
The GCI interface contains: B1, B2, M-
channel, B1* channel.
In ISDN applications, the B1* channel
contains two D-channel bits, 4 C/I bits
with the commands (towards the MTC-
20172 SIC) or the status indications
(from MTC-20172 SIC), and two extra
bits to control the maintenance channel,
MX and MR.
A general overview can be found in
4.6.2. For details see paragraphs:-
Physical Organization : 6.2
B-channels : 6.3
D-channel : 6.4
C/I channel : 6.5
M-channel, MX and MR : 6.6
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6. The GCI Interface
Fig. 6.1 : Relation of Clock, Frame and Data on the GCI bus;
Normal and Inverted (or V*) bus
The clock signal is twice the bit-rate of
the serial data lines. The clock entering
the MTC-20172 SIC can be ANY
multiple of 16 kHz between 512 kHz
and 8192 kHz.
The frame signal has two possible
polarities: GCI style or Inverted.
The MTC-20172 GCI selects
automatically between mode and
inverted mode based on the frame
width.
The GCI frame signal is often a 50%
duty-cycle signal, but only the rising
edge is important. The frame indicates
the bit 0 of channel 0, the first bit of the
frame. If the width of the HIGH part of
the frame signal is narrowed to only one
clock cycle, this indicates a multiframing
request, see 5.9. The narrowing must
run at a cadence of once per 40, 8-kHz
frames.
In the inverted mode (see TABLE 4.1
and Figure 6.1), the descending edge
of the frame is used; it indicates the bit
position -5 before the bit 0 of channel
0. The frame signal is low for only one
cycle of the clock signal. This allows
the automatic recognition of this
mode. The inverted frame sent to the
MTC-20172 SIC is displaced by half
a period of the clock. Note that the
inverted mode will not support
multiframing indication or
synchronization. Extra clock signals
are present on the MTC-20172 SIC to
support other bus related functions
(e.g. CODECs), see tables 4.1a and
4.1b. All clock outputs of the MTC-
20172 SIC are normally derived from
the crystal. However, in the TE and LT-
T modes some clock outputs, marked
with "*" in TABLES 4.1.a & b, are
synchronized with the downlink S-bus
interface.
Details on the timing can be
found in chapter 9.
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Fig. 6.1a : Deactivation of the GCI Interface
6.2.2 Channel Selection
The MTC-20172 SIC will access the first
GCI channel group after the frame
pulse, in all non-multiplexed modes.
In the multiplexed modes, the MTC-
20172 SIC will access a GCI channel
group at the position indicated by the
TSi input pins. (See 4.11 and 4.12).
The MTC-20172 SIC does not allow
some channels to be displaced to other
position in the frame.
6.2.3 DATA Pin Tristate or Open
Drain Operation
The I/O type of the DOUT pin of the
MTC-20172 SIC is found in TABLE 3.3,
in function of the configuration modes of
TABLE 4.1; for electrical and timing
properties, please see chapter 9.
6.2.4 Power-down and Power-
up On The GCI Bus
For maximum power saving, the GCI
bus can be halted completely in the TE
and NT modes.
POWER-DOWN
The principles of the shut down
procedure are shown in Figure 6.1a.
The upstream device is the master of the
bus, and will shut it down by halting the
clock and frame in a low voltage, low
impedance state. The data lines are in a
high voltage and high resistance state
(with a pull-up device).
Before shut-down, all device must
prepare to reactivate the bus or to
recognize the reactivation via the bus.
The time of the shutdown is related to
the C/I channel and the actual
commands and indications. The
upstream master device sends the
deactivate request (DR="0000"), the
downstream device answers with the
Deactivate Indication upstream
(DIu="1111"). The "all one" DIu is
compatible with the idle state of the
upstream data line in an "all one" state.
The bus master waits until it sees the
DIu, and changes the downstream C/I
to "1111" = DId (basic) = DC
(extended). This is the deactivation
confirmation. The master sends DC
exactly 4 times, and shuts the clock
down after the last bit of the fourth
occurrence of the C/I = "1111".
The upstream device can then enter the
complete internal power-down state.
After validating the DC or DId, the
downstream device goes to the idle
state, it will release the upstream data
line completely, which will be held high
by a pull-up resistor.
The downstream device can enter the
power-down state earlier than the
upstream master, only the GCI bus part
must count frame activity and recognize
activity beyond the shut-down instant.
(Indeed, this is recognition of bus
reactivation by the upstream device).
Asynchronous Power-Up Request from
the Downstream Device
If the downstream device wants to
activate the bus, it pulls the upstream
data line low (against the pull-up
resistor).
The upstream bus master recognizes
this as an activation and starts the bus,
as described in the next paragraph.
The downstream device can keep the
data line low until it has recognized the
activity on the GCI bus and it is
synchronized on clock and frame. As
long as the downstream device pulls
down the data line the C/I is "TIM"
("0000" or timing request).
POWER-UP from the Upstream device
The upstream device is awakened by the
network or by the asynchronous power-
up request from the downstream device,
see previous paragraph.
In both cases, the upstream device
simply starts the clock, frame and data
of the bus.
If the downstream device is still in power-
down, the frame signal is recognized by
its GCI bus part. Indeed, it is awakened
by a frame signal edge after the shut-
down instant.
6.2.4.1 MTC-20172 SIC Power-
down and Power-up in NT
Mode
Here, the MTC-20172 SIC is a slave on
the GCI bus.
POWER-DOWN of the MTC-20172 SIC
in NT mode
The general procedure to shut down
the GCI bus (see above) forces the
MTC-20172 SIC into the maximum
power-saving state (3) "Deactivated",
see 6.5.2 and Figure 6.1a.
The DC command deactivates the S-bus
transceiver, the internal clock distribution
and the XTLO output pin (i.e. the 7 MHz
crystal oscillator). If no crystal is used,
the 7 MHz clock on the XTLI pin can be
shut down.
The asynchronous signal detector is
the only active part in the S-bus
transceiver, the GCI part runs no
activity internally, it will only react on
a rising edge of the frame signal, to
start again.
POWER-UP of the MTC-20172 SIC in
NT mode
a) Activation through the S-bus will be
seen by the activity detector.
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Fig. 6.2 : SDL Diagram NT
Extended
Basic
The MTC-20172 SIC does not need
a crystal input or GCI clock to
activate the GCI interface, which it
does by asynchronously pulling the
GCI data line low. The bus master
activates the bus and it must also
deliver the 7 MHz master clock if it is
generated externally of MTC-20172
SIC. If an crystal is used for the
master clock signal, the MTC-20172
SIC will enable the crystal oscillator
when it sends the asynchronous
activation request on the GCI bus.
b) Activation through the GCI bus
consists of clock and frame delivery,
followed by commands via the C/I
channel. MTC-20172 SIC will
activate the S-bus transceiver
according to the commands; it also
starts the crystal oscillator. If the
master clock is generated externally it
must be delivered to MTC-20172
SIC.
In both cases a) and b), a delay of
2ms is needed by the crystal oscillator
to start running.
6.2.4.2 Power-down and
Power-up in TE Mode
In the TE mode, the MTC-20172 SIC is
master of the GCI timing.
POWER-down of the MTC-20172 SIC in
TE mode
The procedure to shut down the GCI bus
(see above) brings the MTC-20172 SIC
into the maximum power-saving state (1)
"Power Down", see 6.5.4 and Figure
6.4.
The DIu command deactivates the S-
bus transceiver, except the activity
detector.
If the ENCK input of MTC-20172 SIC
(see under 4.11 and 4.12) is off, the
MTC-20172 SIC shuts down the GCI
bus, the internal clock distribution, the
XTLO output pin (i.e. the 7 MHz
crystal oscillator), and the extra clock
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Rev. 1.1 February 1997
outputs, shown in TABLES 4.1a & b.
The asynchronous signal detector is the
only active part in the S-bus transceiver,
the GCI part runs no activity internally, it
will only react on a falling edge of the
data input signal.
If ENCK stays active, the crystal, the
GCI bus, and all clock outputs stay
active. The power saving is not optimal.
POWER-UP of the MTC-20172 SIC in
TE mode
Activation through the S-bus is possible.
The signal detector enables the crystal,
the GCI clock and frame is activated,
the receiver hunts for synchronization,
indications and commands are
exchanged via the C/I channel and the
MTC-20172 SIC awaits further
commands.
On activation through the GCI bus, the
controller pulls the data line low (timing
request). The MTC-20172 SIC enables
clock and frame, and C/I codes are
exchanged between the MTC-20172
SIC and the controller.
The controller has an alternative way
to activate the GCI bus in TE mode: It
pulls the ENCK pin active in power-
down, and the MTC-20172 SIC starts
the crystal and delivers the GCI timing
signals and all other clock signals.
Fig. 6.3 : SDL Diagram LT-S
Extended
Basic
Extended
Basic
One major difficulty exists:
Once the MTC-20172 SIC has
acquired synchronization on the
downlink data, the GCI frame must be
adjusted to the received frames.
This is needed to minimize transport
delays of the B-channels. There is an
optimal fixed relation between the
received S-bus frame and the GCI
frame, see 5.5.2.
The locking of the GCI frame to the S-
bus frame causes a jump of the GCI
frame pulse. To limit the number of
phase jumps, the free-running GCI
pulse is only adjusted when the full
synchronization on the
S-bus frames is acquired.
6.2.4.3 MTC-20172 SIC
Power-down and Power-up in
The LT-S/LT-T
In the LT-S/LT-T modes the GCI bus is
not put in power-down. The GCI clock
and frame run continuously.
However, the MTC-20172 SIC can be
forced in a low power state via the
dedicated "1111" command. This is
the "did" or DC command in LT-S and
the DIu command in LT-T, see 6.5.9
and 6.5.10.
The MTC-20172 SIC in LT-S mode
goes to the state (3) "Deactivated",
see 6.5.3 and Figure 6.3.
The MTC-20172 SIC in LT-T mode
goes to the state (1) "Power Down",
see 6.5.4 and Figure 6.4.
This command deactivates the analog
part of the S-bus transceiver, and
partly the internal clock distribution.
The asynchronous signal detector is
the only active part in the S-bus
transceiver, the GCI part will react on
new C/I channel commands and on
M-channel activity, but runs no other
activity internally.
The 7 MHz master clock stays active if
a crystal is used between the pins
XTLO and XTLI.
Special clock pins for the LT-T mode:
As long as the XTLI pin receives a 7
Mhz signal (with crystal or other clock
source), the SCLK 512 kHz* output (in
the LT-T normal mode) or the XTR3
1536 kHz* output (in the LT-T
extended mode) will stay active.
These pins contain a clock signal,
which is normally synchronized on the
S-bus downlink bit-stream, but which
can not be adjusted when the S-bus is
idle.
The SCLK or XTR3 clock will have the
same frequency error as the XTLI clock
signal.
If the clock signal XTLI is shut down,
the SCLK or XTR3 pin will go to an
(undefined high or low) permanent DC
state.
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Fig. 6.4 : SDL Diagram TE, LT-T
6.4 The D-Channels on
the GCI bus
The D-channel contains HDLC
messages.
In NT/LT-S mode the D-channel is
exchanged transparently with the S-
bus.
In TE/LT-T mode there is a D-channel
access protocol on the S-bus, which
limits the transport of the D-channel to
the S-bus, see 5.7.
The TIC bus protocol used by other
divices for D-channel Access control in
an intelligent NT is NOT supported,
see 5.8.
6.3 The B-Channels on
the GCI bus
The B-channels are 64 kbit/s. They
are transparent channels used for a
point-to-point switched connection.
Idle B-channels are often forced at all
binary 1.
In other interface devices, the direction
of the B-channels can be reversed on
the GCI data pins. This is not possible
in the MTC-20172 SIC.
Also, the position of the GCI B-
channels can be moved to alternative
positions. This is not possible with
MTC-20172 SIC.
6.5 The Command/
Indication (C/I)
Channel
The S-bus transceiver must be put in a
defined state according to CCITT
I.430. This happens partially under its
own control and under supervision of
an external controller.
In the C/I channel, commands to and
state indications from the MTC-20172
SIC are exchanged with a control
element (µ-controller) or with an other
uplink or downlink ISDN circuit.
The state diagram of the C/I channel,
the possible commands and
indications, and the internal reaction of
the S-transceiver are all defined in the
GCI standards, which allow a simple
interconnection of uplink and downlink
ISDN elements. Unfortunately, a few
dialects of the C/I exist.
Moreover, some unused commands
and indications can be used for other
purposes (e.g.maintenance/monitoring)
and can be chosen according to the
component manufacturer.
In MTC-20172 SIC, two version
of the C/I command channel are
implemented:
1) The V* version
The C/I channel works according to
the Mietec MTC-2072 SIC. It can be
linked to the MTC-2071 UIC (4B3T) of
MIETEC and the IEC of Siemens at the
NT. The MTC-20172 SIC is fully
compatible, with a few extra
commands available.
2) The GCI version
The C/I channel is compatible with
many other devices. It can be linked to
the UID of ST/NSC and to the 2B1Q
U-device of Siemens.
Compared to the V* version, GCI
incorporates minor changes and
additions. Some commands are coded
with binary numbers differently from
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Fig. 6.5 : Explanation of Notation of the SDL Diagrams
the V*, some indications were split or
added.
For information, the remainder of this
section 6.5 contains:
- 6.5.1 General information of the
C/I state diagrams
- 6.5.2 State Diagram for the NT
position
- 6.5.3 State Diagram for the LT-S
position
- 6.5.4 State Diagram for the LT-T
position
- 6.5.5 The Commands and
Indications of the Basic Mode
- 6.5.6 The Commands and
Indications of the extended Mode
- 6.5.7 C/I Equivalence TABLE
basic/extended modes
- 6.5.8 Commands and Indications
For the NT Applications
- 6.5.9 Commands and Indications
For the LT-S Applications
- 6.5.10 Commands and Indications
For the TE/LT-T Applications
6.5.1 General Information of
the C/I State Diagrams
The state diagrams exist for NT, LT-S,
and the combination TE/LT-T, as
explained in 6.5.2 to 6.5.4.
The STATE DIAGRAMS are shown in
the Figures 6.1 to 6.5. Three
examples of activation and
deactivation are shown in Figures 6.7
to 6.9.
The state names use the names F1 to
F8 and G1 to G4, as used by the
CCITT. However, for a full functional
description, the states need to be
expanded into sub-states. The state
diagrams are almost identical for
Basic and extended Modes, the
differences are minor for NT and LT-T,
and mostly related to the Command/
Indication use. In some cases, hidden
sub-states of the Basic Mode are
expanded to the improved extended
Mode version.
The LT-S diagram is a simplified version
of the NT state diagram. One will notice
that the state numbering of the LT-S is
just a sparser version of the NT-T case.
The TE and LT-T diagrams are identical.
In the state diagrams, each state is
represented by a circle. It contains the
name, the command and indication,
the incoming and outgoing INFO on
the S-bus, as explained in Figure 6.1.
For convenience the states are also
numbered.
The commands and indications are
commented in 6.5.5 to 6.5.10.
The arrows indicate events and
conditions which cause state changes.
The diagrams are functionally
complete, but some arrows are
omitted (unexpected or illegal
commands), and some arrows are
dashed and commented in the text for
clarity.
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Fig. 6.6 : SDL Diagram TE/LT-T, Unconditional states, Basic Mode
Debouncing
The C/I codes are debounced to
prevent accidental errors. The MTC-
20172 SIC accepts a command only
after it is present for 2 consecutive
GCI frames. Normally, the indications
from the MTC-20172 SIC should be
debounced also by the receiving
control unit.
Illegal Commands
The reaction of MTC-20172 SIC to
illegal commands (unknown values of
the command nibble) is No-Operation
Not-Logical C/I Transitions
The MTC-20172 SIC will follow the
C/I-channel commands, even if they
are out of sequence according to the
CCITT.
6.5.2 State Diagram for the NT
Position
STATE NAMES and NUMBERS
(1) G4 Pending Deactivation
This state is reached by the the
unconditional "DR" deactivation
request command. After a timeout of
32 ms, or 16 ms of INFO0 reception
the MTC-20172 SIC goes to state (2).
(2) G4 Unacknowledged
The MTC-20172 SIC is ready to
deactivate, signals "DIu", and waits
for the acknowledgement with
"did"="DC", and prepares the idle
state (see 6.2.4) of the GCI bus.
(3) G1 Deactivated
The MTC-20172 SIC is not
transmitting. No signal is detected, no
activation is commanded. This state is
closely linked with the state 12.
(4) G1 INFO1 Detected
INFO1 detected (actually, any AMI
signal). MTC-20172 SIC goes through
the GCI bus activation, requesting
timing signals with the "TIM" indica-
tion (see 6.2.5), then indicates "ARu".
The MTC-20172 SIC waits for the the
"ARd" command from uplink device
(e.g. U interface) once the U-link
synchronizes.
(5) G2 Pending Activation
"ARd" forces the MTC-20172 SIC to
send INFO2, and to try to detect and
sync on INFO3. "ARL" also activates
the analog loop from TX to RX on the
S-bus transceiver.
(6) G2 Synchronized
MTC-20172 SIC achieved INFO3 syn-
chronization, MTC-20172 SIC signals
"AIu" and waits for "AId" (or AIL) to
go to the G3 state. The MTC-20172
SIC signals "AIu". ARL (the loop 2
case) forces the analog loop and the
receiver synchronizes on INFO2.
(7) G3 Activated (with or without
loop 2)
Receiving "AId" (or AIL) MTC-20172
SIC switches INFO2 to INFO4,
provided the receiver synchronizes on
INFO3: cut through of the B and D
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Fig. 6.7 : Activation Sequence Outgoing CallFig. 6.7 : Activation Sequence Outgoing Call
GCI GCI
channels. The MTC-20172 SIC signals
"AIu". AIL (the loop 2 case) forces the
analog loop and the receiver
synchronizes on INFO4.
(8) G2 Unsynchronized
If the S-bus receiver loses synchroniza-
tion on the incoming INFO3, it switches
to INFO2 downlink transmission, and
signals "RSYu". In the Basic Mode, this
state is hidden in the previous state (7).
(9) Lost Framing at U-side
If the U-link loses synchronization, it
indicates this with the RSYd command.
Here, some fundamental difference
exists between Basic and extended
Modes, discussed further down under
remark 11.
(10)-(11) Test-mode 1 and Test-
mode 2
The unconditional commands TM1,
TM2, SSZ and SCZ (or the equivalent
pins TM1-, TM2-, SSZ- and SCZ-, see
4.11, 4.12) force the MTC-20172 SIC
into test-mode 1 (Send Single Zeros) and
test-mode 2 (Send Continuous Zeros)
(12) Reset
In the state diagrams of the Basic and
extended Modes, the reset is shown dif-
ferently. However, for the Basic mode,
the reset state (12) is a sub-state hidden
in state (3). In the MTC-20172 SIC, the
split states (3) and (12) are implemented
for the Basic and extended modes.
INFO0 is sent and the incoming INFO
is ignored.
6.5.2.1 NT State Diagram:
Remarks and Implementation
Remark 1 : During the test-modes, the
MTC-20172 SIC request timing with
"TIM". This also applies if the test-modes
are commanded via pins (see 4.11,
4.12). Indeed, without TIM the NT clocks
are not activated and MTC-20172 SIC
would not receive the Xtal clock.
Remark 2 : a number of non-logical
commands could be received at
various states of the diagram. The
unexpected RSYd, AId, AIL, etc... will
force the correct states, with the
appropriate indications. The incorrect
issuing of the deactivate confirmation
command "did"="DC" will force the
state (1). However, the power down
of the GCI bus (clocks, frame etc, ...)
can only be guaranteed if the correct
"DR" is used. See 6.2.4.
Remark 3 : There are some dashed
arrows in the state diagram: The
device will not return to state (5) when
an unexpected AR is given during
state (9). The latest GCI state diagram
appears to pass through the state (5)
only once, all subsequent loss-of-sync
events are indicated with RSYu from
state (8). To simplify the MTC-20172
SIC there will be no difference
between basic and extended modes,
and the dashed arrows are NOT
implemented.
Remark 4 : During the G4 pending
deactivation state, the basic mode
indicates RSYu, LSL or AIu, the
extended mode indicates TIM. This
difference is implemented.
Remark 5 : The "lsl" indication is
deleted from the basic states. If the
device receives no signal, it will go
out of synchronization after only 2
missing frames. LSL is replaced by
RSYu, as is done for the extended
mode.
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Fig. 6.8 : Activation Sequence Incoming Call
GCI GCI
Remark 6 : The reaction of MTC-
20172 SIC on the AR command is not
required. However, the MTC-20172
SIC reacts on AR in state (1) as
indicated.
Remark 7 : If an accidental signal
on the S-bus (spike, EMC, ...) awakens
the MTC-20172 SIC, which goes to
state (4), the only way to return to
idle, state (3), is via the normal
activation and deactivation procedure.
Remark 8 : In the state (9), the
extended mode always answers with
RSYu; the basic mode can also signal
LSL and AIu, depending of the
receiver state. However, the MTC-
20172 SIC suppresses the LSL and
AIu indication during state (9).
Remark 9 : The command TM2 (test-
mode 2) exists only for the extended
mode. It could be considered illegal
for the basic mode and result in NO-
Operation. However, the implementa-
tion extends the TM2 command to the
basic mode.
Remark 10 : The "ei" indication,
i.e. both RSTB and SCZ- pin active, is
valid for the extended mode. The indi-
cation during active RSTB pin is TIM.
Remark 11: In state (9), the MTC-
20172 SIC sends INFO2 for ALL NT
modes. This is the most logical respon-
se. It keeps the S-bus active and
synchronous, with the B and D-chan-
nels downlink idle at all zero. Uplink
the B-channels are transparent, but the
D-channel will be idle, because the E-
channel downlink is forced to all zero.
Note that the multiframing S/Q-
channel will work also during INFO2!.
Remark 12 : In the loop modes
under command of ARL and AIL the
receiver sees the INFO2/4 of its own
transmitter as uplink signal instead of
actual INFO3. It ignores activity detec-
tion on the real S-bus. This bus will
activate normally, because the loop is
a transparent loop 2. The TEs could
even try to send LAPD messages, but
they are not terminated correctly.
6.5.3 State Diagram for the LT-S
Position
The state diagram of the LT-S is a
sparse version of the NT. The same
numbers and names are used. The
Figure of the state diagram is
organized with identical states on the
same position, with deletion of missing
states. The states (4), (6) and (9) do
not exist in the LT-S case.
State Names and Numbers
(1) G4 Pending Deactivation
This state is reached by the the uncon-
ditional "DR" deactivation request
command. After a timeout of 32 ms,
or 16 ms of INFO0 reception, the
MTC-20172 SIC goes to state (2).
(2) G4 Unacknowledged
The MTC-20172 SIC is ready to
deactivate, signals "DIu", and waits
for the acknowledgement with
"did"="DC", and prepares the
internal idle state (see 6.2.4).
However, the GCI bus will not go to
idle.
(3) G1 Deactivated
The MTC-20172 SIC is not
transmitting. No signal is detected, no
activation is requested. This state is
closely linked with the state 12, which
is only defined for the extended mode.
(5) G2 Pending Activation
There are two ways to arrive in this
state:
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Fig. 6.9 : Desactivation Sequence
GCI GCI
Either :
a) INFO1 is detected (actually any
AMI signal). MTC-20172 SIC
indicates "ARu". Without waiting
for the "ARd" command, the MTC-
20172 SIC activates the S-bus
(INFO2).
Or :
b) "ARd" forces the MTC-20172 SIC
to send INFO2. "ARL" also
activates the analog loop from TX
to RX on the S-bus transceiver.
In both cases a) and b), the INFO2
forces the TEs to respond with INFO3.
The MTC-20172 SIC tries to
synchronize and goes to state (7)
when this happens. In loop case the
receiver sees INFO2/4.
(7) G3 Activated (with or without
loop 2)
MTC-20172 SIC achieved INFO3
synchronization, MTC-20172 SIC sig-
nals "AIu" and goes to "cut-through"
by sending INFO4. ARL (the loop 2
case) forces the analog loop and the
receiver synchronizes on INFO2/4.
(8) G2 Unsynchronized
If the S-bus receiver loses synchroniza-
tion on the incoming INFO2/3/4 in
state (7), it switches to INFO2
downlink transmission and signals
"RSYu". In the basic mode, this state is
hidden in the previous state (7).
(10)-(11) Test-mode 1 and Test-
mode 2
The unconditional commands TM1,
TM2, SSZ and SCZ force the MTC-
20172 SIC in test-mode 1 (Send
Single Zeros) and test-mode 2 (Send
Continuous Zeros)
(12) Reset
In the state diagrams of the reset is
shown differently. However, for the
basic mode, the reset state (12) is a
substate hidden in state (3). In the
MTC-20172 SIC, the split states (3)
and (12) are implemented.
INFO0 is sent and the incoming INFO
is ignored.
6.5.3.1 LT-S State Diagram:
Remarks and Implementation
Some remarks are the same as those
listed under the NT description.
Remark 1 : During test-modes, the
MTC-20172 SIC indicates "TIM", see
Remark 1, NT case.
Remark 2 : In all states, all listed LT-
S commands can be issued. Even the
DC command without the normally
preceding DR is allowed. Indeed, the
strict power-down of the bus is not
needed. The MTC-20172 SIC simply
goes to an internal low-power state.
See also 6.2.4.
Remark 3 : During the G4 pending
deactivation state, the basic mode
indicates RSYu, LSL or AIu, the ex-
tended mode indicates TIM. This
difference is implemented in the SIC.
Remark 4:The "lsl" indication is
deleted from the basic mode states. If
the device receives no signal it will go
out of synchronization after only 2 mis-
sing frames. LSL is replaced by RSYu,
as is done for the extended mode.
Remark 5 : The command RES (soft
reset) exists only for the extended
mode.
Remark 6 : The command TM2 (test-
mode 2, binary "0011") exists only
for the extended mode. It could be
considered illegal for the basic mode,
and result in NO-Operation. However,
the implementation extends the TM2
command to the basic mode.
Remark 7 : In the loop modes under
command of ARL and AIL, the receiver
sees the INFO2/4 of its own transmit-
ter as an uplink signal instead of the
actual INFO3. It ignores activity detec-
tion on the real S-bus. This bus will
activate normally, because the loop is
a transparent loop 2. The TEs could
even try to send LAPD messages, but
they are not terminated correctly.
Remark 8 : The reaction of MTC-
20172 SIC on the AR command from
state (1) is not required. However,
MTC-20172 SIC reacts on AR in state
(1) as indicated.
6.5.4 State Diagram for the
TE/LT-T Position
(See also fig. 6.6).
State Names and Numbers
(1) F3 Power Down
The MTC-20172 SIC is not
transmitting. The receiver activity
detector is on, but no signal is
detected; no activation is
commanded.
Clock outputs (TE case only) are
inactive, unless the ENCK- pin is
forced low. In TE, the power-down is
maximum.
(2) F3 Power Up
The TIM command request is given
and MTC-20172 SIC answers with
PU, unless the CON pin is inactive,
see 4.11, 4.12. Then DIS is indicated.
If the ARp command is given with the
CON pin inactive this state is also
reached.
(3) F4 Pending Activation
The command AR8 or AR10 force
MTC-20172 SIC to send INFO1, as
long as INFO0 is received in return.
Software must implement the INFO1
timeout, i.e. timer T3 of CCITT I.430.
Any AMI downlink signal (=not
INFO0) stops the INFO1 uplink. The
detection time is 50 µs when INFO2
comes in. MTC-20172 SIC goes to
state (4).
If the ARp command is given with the
CON pin inactive, the MTC-20172
SIC goes to state (2).
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
(10)-(11) Test-mode 1 and Test-
mode 2
The unconditional commands TM1,
TM2, SSZ and SCZ force the MTC-
20172 SIC in test-mode 1 (Send
Single Zeros) and test-mode 2 (Send
Continuous Zeros)
(12)-(13) Loops
The loops are a special case: It is a
loop 3 type. It links the transmitter
output to the receiver, but only
internally, without transmitting signal
on the uplink S-bus.
The ARL command forces the
transmitter to send INFO3. The
receiver activity detector stays linked
to the downlink signals. The rest of the
receiver sees the looped signal. If the
receiver is NOT synchronous yet the
MTC-20172 SIC is in state (12). Once
the receiver is synchronous MTC-
20172 SIC will be in state (13). B and
D-channels are now looped with a
fixed delay.
The indications differ between basic
and extended modes, and are shown
on Figures 6.5 and 6.6.
If the activity detector sees a downlink
signal, it warns with a special
indication "ATI" (basic mode) or
"RSY" (extended mode).
(14) Reset
The RESET state is an idle state.
Analog parts of the S-bus transceiver
are off. Incoming INFO2/4 is
ignored. Clocks are supplied. Digital
outputs are active.
MTC-20172 SIC will reach the RESET
state when forced via the RST- pin or
the reset C/I command.
6.5.4.1 TE/LT-T State Diagram:
Remarks and Implementation
Remark 1: RST- pin effect and
implementation. The RST- pin force the
device in state (1) (F3 Power Down). It
forces the device in state (14) (RESET).
Both devices go to the RESET state
when commanded via the C/I RESET
command.
The RST- pin and the RESET command
always force the MTC-20172 SIC to
the RESET state.
Remark 2: The CON pin must only
be tested to send INFO1 on the S-bus.
If INFO2 or INOF4 is received
downlink, INFO3 is sent without
checking the CON condition.
Remark 3: Some of the transitions in
the state diagram will never occur.
They are marked with dashed lines.
Implementation is simplified. Indeed,
loss of synchronization will be seen
first, long before the confirmation of
the loss of signal (i.e. INFO0) is valid.
However, a long timeout for INFO0
validation is implemented.
(4)/(8) F5/F8 unsynchronized
This state can be reached from all
other states, when some activity is
detected downlink after idle, or when
synchronization is suddenly lost but
with signal still assumed present. MTC-
20172 SIC tries to synchronize. MTC-
20172 SIC sends INFO0. If it was
sending INFO1 in state (3), it will
cease doing so.
(5) F6 Synchronized
MTC-20172 SIC achieved INFO2
synchronization. Automatically it
responds with INFO3. It waits for
INFO4. Reaching this state from the
power down state (1) takes less than
6 ms, when MTC-20172 SIC is
activated by INFO 2/4 from an uplink
NT or LT-S.
(6) F7 Activated
MTC-20172 SIC achieved INFO4
synchronization. Automatically it
responds with INFO3. It is now in cut-
through. The transition from (5) to (6),
or from INFO2 to INFO4, takes less
than 0.5 ms.
7) Slip detected
This state is hidden in the basic mode.
The Slip detection is normally send for
0.5 ms (i.e 4 times) on the C/I
channel. The internal elastic buffer is
adjusted, which causes a number of
bytes to be lost or repeated in the
B-channels, and bit errors on the
D-channel.
(8) F8 lost framing
This state (basic mode) is now merged
with the state (4).
(9) F3 Pending Deactivation
When the MTC-20172 SIC sees
INFO0 (after 16 ms) it signals "DR",
deactivation request. When receiving
INFO again it reactivates to state (4).
To reactivate the S-bus from the TE
side, MTC-20172 SIC must first be put
in state (1) or (2) with DIu or TIM.
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
6.5.5 The Commands and Indications of the Basic Mode
The MTC-20172 SIC implements the full list of C/I codes of the basic mode as
indicated below:
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table 6.1: The Original Basic Mode Commands and Indications
mode Terminal equipm. network termin. line termination
TE/LT-T NT LT-S
C/I Downstr Upstr. Downstr Upstr. Downstr Upstr.
code Indicat. Command Command Indicat. Command Indicat.
0000 DR TIM DR TIM DR -
0001 - RS [RES]+ (lsl)! scz (lsl)!
0010 sd SSZ SSZ - SSZ -
0011 dis [TM2]+ [TM2]+ - [TM2]+ -
0100 RSY scz RSYd RSYu - RSYu
0101 - - - - - -
0110 ei - - ei - -
0111 PU - - - - -
1000 ARd AR8 ARd ARu ARd ARu
1001 - AR10 - - - -
1010 ti ARL ARL - ARL -
1001 ati - - - - -
1100 AI8 - AId AIu - AIu
1101 AI10 - - - - -
1110 - - AIL - - -
1111 DID DIu DID DIu DID DIu
Comments:
[]+: The command "testmode2" =
TM2 (=scz) and "soft reset" = RES
(=RS) are added at unused positions
to remove differences between modes.
!: The lsl indication was deleted,
because its effect is equivalent with
the RSYu indication.
The C/I of the basic mode are not
according to the final GCI standard.
The commands which differ
functionally from the final GCI are put
in lower case.
For C/I names which differ only for
the upstream and downstream
indication, are added lower case "d"
and "u".
The detailed explanation of each
command is given below in 6.5.8 to
6.5.10.
6.5.6 Extended Mode Commands and Indications
The MTC-20172 SIC implements the full list of C/I codes of the extended mode
as indicated below:
54
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table 6.2: Extended mode commands and indications
mode Terminal equipm. network termin. line termination
TE/LT-T NT LT-S
C/I Downstr Upstr. Downstr Upstr. Downstr Upstr.
code Indicat. Command Command Indicat. Command Indicat.
0000 DR TIM DR TIM DR TIM
0001 RES RES RES - RES -
0010 TM TM1 TM1 - TM1 -
0011 SLIP TM2 TM2 - TM2 -
0100 RSY [scz]+ RSY RSY - RSY
0101 - - - - - -
0110 - - - [ei]+ - -
0111 PU - - - - -
1000 AR AR8 AR AR AR AR
1001 - AR10 - - - -
1010 ARL ARL ARL - ARL -
1001 - - - - - -
1100 AI8 - AI AI - AI
1101 AI10 - - - - -
1110 AIL - AIL - - -
1111 DC DI DC DI DC DI
[]+: The commands "scz" (=TM2) and
"ei" were added to remove
differences between modes.
This list follows the stable GCI version
of the names, abbreviations and
positions of the C/I codes.
The detailed explanation of each
command is given below in the 6.5.8
to 6.5.10.
The NT-STAR C/I channel issue:
The MTC-20172 sic does not support
the functional combination of the c/I
codes in the nt-star configuration.
If two SICs in an NT are put in STAR
configuration, see 5.6.1, the C/I
channels will coincide on the GCI bus.
The DOUT pin is configured as open
drain (see TABLE 3.3), thus no electrical
problems exist. However, the indications
of both SICs will be wired-ANDed on
the bus, bit by bit, and the result is
incorrect. E.g., when one branch of the
STAR has no TE, then it is not
synchronous and it signals "RSY", while
the other branches try to indicate "AI".
The combination is still "0100", which is
"RSY".
NOTE: Some devices use the CEB pin,
which links all devices in the NT-STAR,
to allow the AI uplink indications in the
C/I channel, when at least one device
reaches the G3 Activated state (5). The
MTC-20172 SIC does not support this.
6.5.7 C/I Equivalence Table
The C/I codes are identical for all
functional modes. The C/I codes for
the extended mode (GCI) are more
logically organized and kept identical
over the different modes.
IDENTICAL commands and indications
which use the same abbreviation are
marked as a single C/I in UPPER
CASE. IDENTICAL C/I have
sometimes the same abbreviation
except for the letters "u" and "d"
(uplink an downlink). Those are
marked as single C/I in Mixed Case.
All commands and indications which
have different abbreviation but same
meaning and on the same position
have the equal sign "=".
The basic command in lower case, the
extended command in upper case.
All commands and indication which
are different but on the same position
are marked with the star sign "*", C/I
for basic mode at the left.
Unused positions are marked "-".
Some positions are NOT USED BY
ONE DEVICE ONLY; then they are
marked with both "-" and "*".
Some of the mixed command and indi-
cation codes (i.e. used * unused) are
merged in the MTC-20172 SIC. This is
marked with "&". The command used
in one device is allowed in the unused
position of the other device. Some
mixed indication (i.e. used * unused)
can also be merged: The lsl indication
is deleted, the ei indication will also
appear in the NT extended mode.
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table 6.3: Equivalence table, Basic versus Extended Mode
mode Terminal equipm. network termin. line termination
TE/LT-T NT LT-S
C/I Downstr Upstr. Downstr Upstr. Downstr Upstr.
code Indicat. Command Command Indicat. Command Indicat.
0000 DR TIM DR TIM DR - *TIM
0001 - * RES rs=RES -& *RES (lsl)*&- scz*RES (lsl)*&-
0010 sd * TM ssz=TM1 ssz=TM1 - ssz=TM1 -
0011 dis*SLIP -& *TM2 -& *TM2 - -& *TM2 -
0100 RSY scz* &- RSYd RSYu - RSYu
0101 - - - - - -
0110 ei * - - - ei * &- - -
0111 PU - - - - -
1000 ARd AR8 ARd ARu ARd ARu
1001 - AR10 - - - -
1010 ti * ARL ARL ARL - ARL -
1001 ati * - - - - - -
1100 AI8 - AId AIu - AIu
1101 AI10 - - - - -
1110 - * AIL - AIL - - -
1111 did=DC DIu did=DC DIu did=DC DIu
* Marks functional differences
(17 in total).
& Marks functional differences which
can be merged for both modes.
Table 6.4.a : MTC-20172 SIC C/I : NT overview
NT Downstr Upstr. Downstr Upstr.
Command Indicat. Command Indicat
0000 DR TIM 1000 ARd ARu
0001 -& * RES (lsl)*&- 1001 - -
0010 ssz=TM1 - 1010 ARL -
0011 -& * TM2 - 1001 - -
0100 RSYd RSYu 1100 AId AIu
0101 - - ++ 1101 - -
0110 - ei * &- 1110 AIL -
0111 - - 1111 did=DC DIu
6.5.8 Command and Indications for NT Applications
++ MAIC is NOT implemented.
* Marks functional differences
(4 in total).
& Marks functional differences which
are merged for both devices.
6.5.8.1 Commands (Downstream) in NT Mode
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Table 6.4.b : MTC-20172 SIC commands (DS) NT
0000 DR # Deactivate Forces MTC-20172 SIC to deactiv. the S-bus (=INFO0)
Request followed by DIu and did=DC
0001 *RES # RESET Forces MTC-20172 SIC to soft reset, extended mode only,
& MTC-20172 SIC accepts it in basic mode (merged)
0010 ssz # TEST-MODE 1 Forces MTC-20172 SIC to test-mode 1, sending
= TM1 single zeros
0011 *TM2 # TEST-MODE 2 Forces MTC-20172 SIC to test-mode 2, extended mode
& only, sending continuous zeros, command is
extended to the basic mode of the MTC-20172 SIC
0100 RSYd Resynchon- The U-interface is not synchronous, MTC-20172 SIC
izing down sends INFO2 {or SCZ}, see remark 1 below
1000 ARd Activation MTC-20172 SIC forced to INFO2 transmission,
Request down receiver indicates the S-bus reaction
1010 ARL Activat. req INFO2 transmission on the S-bus
with S-loop test loop2 switched (transparent loop)
1010 AId Activation INFO4 transmission, normally only after
Indication AIu indication is received
1010 AIL Activ. Indic. INFO4 transmission
with S-loop test loop2 switched (transparent loop)
1111 did= Deactivate Deactivation confirmation, entering the
DC Confirmation power down state, INFO0 sent, critical
timing to halt the clocks, see 6.2.4
* Marks functional difference;
& Marks differences that are merged.
# Unconditional commands, which
force an unambiguous state.
Remark 1: When the U-interface is
resynchronizing, the basic mode sends
Continuous Zeros, the extended mode
sends INFO2. MTC-20172 SIC will
send INFO2.
Remark 2: During loops, the MTC-
20172 SIC simply ignores the incoming
INFO3 from the S-bus. The receiver
synchronizes on looped INFO2/4.
6.5.8.2 Indications (Upstream) in NT Mode
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Table 6.4.c : MTC-20172 SIC indications (US) NT
0000 TIM Timing The MTC-20172 SIC requires GCI clocks and also
Request Master clock input, if no crystal is used.
0001 *lsl Lost Signal No receive level,
& Level indication deleted, replaced by RSYu
0100 RSYu Resynchron- The S-bus receiver tries to synchronize
izing
0101 --------- --------- ---------
0110 * ei Error RSTB and SCZ- pin both low simultaneously
& Indication Only in basic mode, but is
extended to theextended mode
1000 ARu Activation INFO1 received (actually any AMI signal)
Request up
1100 AIu Activation Receiver synchronized on INFO2/3/4
Indication up (INFO3 normally, INFO2/4 in loop)
1111 DIu Deactivation Timer (32 ms) expired, or INFO0 received
Indication (16 ms) after DR (deactiv. request)
* Marks functional difference;
& Marks differences that are merged.
"lsl" and "ei" are NOT implemented.
Remark 1: The "lsl" indication is
deleted from the command list and
replaced by RSYu. If the devicedoes
not receive a valid signal, e.g. no
signal, it will go to the loss of sync
state, and it signals loss of sync.
Remark 2: The "ei" indication is
extended to the the extended mode,
without any problems.
Note also comments in REMARK [10]
in 6.5.2.1.
6.5.9 Commands and Indications LT-S
* Marks functional differences
(3 in total).
& Marks functional differences which
are merged for both devices.
Table 6.5.a : MTC-20172 SIC C/I LT-S
LT-S Downstr Upstr. Downstr Upstr.
Command Indicat. Command Indicat
0000 DR - *TIM 1000 ARd ARu
0001 scz*RES (lsl)*-& 1001 - -
0010 ssz=TM1 - - 1010 ARL -
0011 -& *TM2 - - 1001 - -
0100 - RSYu 1100 - AIu
0101 - - 1101 - -
0110 - - 1110 - -
0111 - - 1111 did=DC DIu
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6.5.9.1 Commands (Downstream) In LT-S Mode
Table 6.5.b : MTC-20172 SIC commands (DS) LT-S
0000 DR # Deactivate Forces MTC-20172 SIC to deactiv. the S-bus (=INFO0)
Request followed by DIu and did=DC
0001 *RES # RESET Forces MTC-20172 SIC to soft reset, extended mode
has "scz" meaning for basic mode
*scz # Send Continu- Forces MTC-20172 SIC to test-mode 2, extended mode
ous Zeros has RESET meaning for extended mode
0010 ssz # TEST-MODE 1 Forces MTC-20172 SIC to test-mode 1, sending
= TM1 single zeros
0011 *TM2 # TEST-MODE 2 Forces MTC-20172 SIC to test-mode 2
1000 ARd Activation INFO transmission, first INFO2, then
Request down INFO4 once receiver is synchronous
1010 ARL Activat. req INFO transmission on the S-bus
with S-loop test loop2 switched (transparent loop)
1111 did= Deactivate Deactivation confirmation, entering the
DC Confirmation power down state, INFO0 sent
* Marks functional difference;
& Marks difference that can be merged.
# Unconditional commands, which
force an unambiguous state.
Remark 1: During loops the MTC-
20172 SIC simply ignores the
incoming INFO3 from the S-bus. The
receiver synchronizes on looped
INFO2/4.
Remark 2: The TM2 command
could be extended to the basic mode.
Remark 3: RES and scz commands
cannot be merged
6.5.9.2 Indications (Upstream) In LT-S Mode
Table 6.5.c : MTC-20172 SIC indications (US) LT-S
0000 *TIM Timing The MTC-20172 SIC requires GCI clocks and
Request Master clock input, extended mode only
(Extention to basic mode impossible)
0001 *lsl Lost Signal No receive level, indic. Basic mode only,
& Level indication deleted, replaced by RSYu
0100 RSYu Resynchron- The S-bus receiver tries to synchronize
izing on incoming INFOx
0101 --------- --------- ---------
1000 ARu Activation INFO1 received (actually any AMI signal)
Request up
1100 AIu Activation Receiver synchronized on INFO2/3/4
Indication up (INFO3 normally, INFO2/4 in loop)
1111 DIu Deactivation Timer (32 ms) expired, or INFO0 received
Indication (16 ms) after DR (deactiv. request)
* Marks functional difference; & Marks difference that can be merged.
Note that this list is identical to the NT
indication list, except for the "ei"
indication, which is not present here.
Remark 1: The "lsl" indication is
deleted from the basic command list
and replaced by RSYu. If the device
does not receive a valid signal, e.g.
no signal, it will go to the loss of sync
state, and it signals loss of sync.
Remark 2: The TIM indication is
used in the NT modes. However, in
the LT-S modes here it is only listed for
the extended mode. Because the
"TIM" indication is not expected from
the basic mode, it cannot be allowed
it to appear in the C/I channel in LT-S
modes of the MTC-20172 SIC. As the
GCI bus is never shut down in LT-S
modes, the timing request "TIM" is not
needed.
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6.5.10 Commands and indications TE/LT-T
General comments:
The difference between the TE and LT-
T modes will be the absence of the
SLIP or "sd" indications. In TE the
MTC-20172 SIC generates its own
clocks.
Table 6.6.a : MTC-20172 SIC C/I TE/LT-T
TE/ Downstr Upstr. Downstr Upstr.
LT-T Indicat. Command Indicat. Command
0000 DR TIM 1000 ARd AR8
0001 - *RES rs=RES 1001 - AR10
0010 sd * TM ssz=TM1 1010 ti * ARL ARL
0011 dis*SLIP -& *TM2 1001 ati * - -
0100 RSY scz* &- 1100 AI8 -
0101 - - 1101 AI10 -
0110 ei * - - 1110 - *AIL -
0111 PU - 1111 did=DC DIu
* Marks functional difference;
& Marks difference that can be merged.
# Unconditional commands, which force an unambiguous state.
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6.5.10.1 Commands (Upstream) in TE/LT-T Mode
Table 6.6.b : MTC-20172 SIC commands (US) TE/LT-T
0000 TIM # TIMING MTC-20172 SIC receives clocks (GCI ..)in LT-T,
it must activate the clocks in TE mode
0001 rs= # RESET Forces MTC-20172 SIC to soft reset
= RES
0010 ssz # TEST-MODE 1 Forces MTC-20172 SIC to test-mode 1,
= TM1 sending single zeros
0011 *TM2 # TEST-MODE 2 Forces test-mode 2, sending continu. zeros
&
0100 *scz # Send Continu. Forces test-mode 2, sending continu. zeros
& Zeros
1000 AR8 Activation Activation command, D channel priority 8/9
Request 8 INFO1, unless the CON pin is not high
followed by INFO3, without CON condition
1001 AR10 Activation Activat. command, D channel priority 10/11
Request 10 INFO1, unless the CON pin is not high
followed by INFO3, without CON condition
1001 AR10 Activation Activation command, D channel
Request 10 priority is 10
1010 ARL # Activ. loop 3 This loop is not transparent, it is a
special case, see text 6.5.4
1111 DIu Deactivate GCI clock can be disabled by MTC-20172 SIC together
Indication with other clocks see 6.2.4
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6.5.10.2 Indications (Downstream) in TE/LT-T Mode
Table 6.6.c: MTC-20172 SIC common indications
(Downstream) in LT-T mode
0000 DR Deactivation Deactivation request via S/T-bus: state F3
Request reached in state diagrams
0100 *RSY Receiver Signal Received (INFO 2/4) but receiver
synchronising not synchronous. It has a special meaning
during loop test in the extended mode :
It signals detection of a signal on the
S-bus, while the rest of the receiver is
linked to the looped S-bus signal
0111 PU Power Up GCI interface clocking is provided {TE?}
acknowledges TIM, and other commands
1000 ARd Activate INFO2 is received, INFO3 send uplink, CON
Request downl pin does not influence INFO3 TX
1100 AI8 Activate INFO4 is received, INFO3 send, priority
indication 8 on D-channel is 8, acknowledges AR8
1101 AI10 Activate INFO4 is received, INFO3 send, priority
indication 10 on D-channel is 10, acknowledges AR10
1111 did Deactivate Clocks will be disabled in TE, see 6.2.4
=DC confirmation MTC-20172 SIC in quiescent state
Table 6.6.d: MTC-20172 SIC indications
(Downstream) Basic Mode only, TE/LT-T mode
0010 sd Slip Detected The frame buffer slipped, cause is wander
=SLIP meaning identical to SLIP for SBCX 2081
0011 dis Disconnected Pin CON connected to GND, INFO1 disabled.
0110 ei Error Acknowledges that RSTB and ENCK pin both
indication or that RS command is given
1010 ti Testmode Indicates that test mode i is commanded
indication with "ssz", "scz", or that the receiver
synchronizes on loop 3 signal after ARL
1001 ati Awake Test Indicates incoming INFOx during test modes
indication with loop 3. Detection of signal via
level detection only. This command is
replaced by RSY during ARL in the extended mode
Comments:
The RES indication of the extended
modeis found as "ei" in the basic
mode.
The "ati" indication exists only in
basic mode, but the extended mode
uses the RSY indication during the
loop (i.e. when ARL command is
given) to indicate an incoming signal.
The basic mode does not have the ARL
indication, which it replaces by PU
during the loop (i.e. when ARL
command is given).
The basic mode has only one
indication “ti”, which is equivalent to
either TM or AIL of the extended
mode.
The subtle differences between the
indications are seen in the State
diagrams explained in 6.5.4, Figures
6.4, 6.5 and 6.6.
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Table 6.6.e: MTC-20172 SIC indications
(Downstream) Extended Mode only, TE/LT-T mode
0001 RES Reset Acknowledges the RES command entering
(optional in GCI spec)
0010 TM Testmode Acknowledges that TM1/TM2 command enters
(optional in GCI spec)
0011 SLIP Slip Detected The frame buffer slipped, cause is wander
=sd Meaning identical to "sd" for basic mode
1010 ARL Activate Acknowledges ARL, loop 3 closing, MTC-20172 SIC
Request loop sends INFO3/4 not transparent to S-bus,
receiver not synchronous on the looped
signal; replaced by PU in the basic mode
1110 AIL Activate Ind. Acknowledges ARL, loop 3 closing, MTC-20172 SIC
with loop receiver synchronous, i.e activation ind.
replaced by ti in the basic mode
Fig. 6.10 : SDL Diagram TE, LT-T, Unconditional states,
extended mode
6.6 M-Channel + MX +
MR : Physical Layer
The M-channel is a byte oriented
channel, where each byte is presented
by the transmitter and acknowledged by
the receiver. The bytes are organized in
messages.
Use and Compatibility
The M-channel should not be used in the
basic mode. The M-channel is an
additional feature.
For compatibility, a special BUSY bit
is present in the M-channel, see 7.4.
Content of the M-Channel
The content is explained in chapter 7.
The length of all MTC-20172 SIC
messages is 2 bytes.
Half-Duplex Operation
The GCI standard allows the two M-
channels to work only half-duplex. This
half duplex operation is implemented
to reduce the internal buffer capacity
of the M-transceiver.
Thus, the MTC-20172 SIC can NOT
send and receive the M-channel
simultaneously. After each received
message (of exactly 2 bytes) the M-
transceiver changes direction, if a
message must be sent in the opposite
way.
Bidirectional Operation:
Message priority
The M-transceiver gives priority to
outgoing messages, to avoid internal
buffer overflow.
The controller on the M-channel must
acknowledge the messages leaving the
MTC-20172 SIC before the MTC-
20172 SIC is able to receive any new
message.
Failing to acknowledge the message
from the MTC-20172 SIC results in a
DEADLOCK: the MTC-20172 SIC waits
for the acknowledge of the outgoing
message, and in the meantime refuses
to acknowledge the next incoming
message.
Operation Speed
The operation speed of the M-channel is
variable: the devices can delay the
transfer by retarding the acknowledge
or by delaying the delivery of
subsequent bytes.
The MTC-20172 SIC will adjusts to any
lower speed on the channel, but it can
transfer one M-channel byte in 250 µs
(both RX and TX). However, this speed
is limited by the half duplex operation,
and by the idle which must follow each
double byte message.
6.6.1 M-Channel Activity
The M-channel can only work when the
GCI interface has its clock and frame
running.
6.6.2 M-Channel Format, Bit and
Byte Numbering Convention
The M-channel is a byte oriented
channel. Bytes (also called octets) are
transmitted in ascending numerical
order. Within a byte the most significant
bit is transmitted first.
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Fig. 6.11 : SDL Diagram of the M-Channel Receiver
The four most significant bits of the first
message byte represent a general
address, discussed under 7.2.
6.6.3 Byte Transfer Procedure
To transfer a message composed of
subsequent bytes on the GCI M-
channel, each byte is presented by the
transmitter and acknowledged by the
receiver. For that purpose, the two M-
channels (to and from the MTC-20172
SIC) have separate handshake bits,
the MR and MX bits in the B1*-
channel, see Figure 4.2.
The MX bit signals the presence of new
information in the M-byte, the MR bit
signals the reading of the information
by the receiver.
State Diagram and Examples of
Message Passing
Simplified state diagrams of the coupled
receiver and transmitter and examples
of message exchanges can be found in
Figures 6.10 to 6.13. Comments on the
state diagram are found in 6.6.4.
6.6.3.1 Idle M-Channel
The procedure start from idle, where
MX and MR are both inactive at 1. The
M-channel content during idle is invalid
and should be at FFh.
However, the idle value received by the
MTC-20172 SIC is ignored.
On the other hand, for compatibility
reasons, the fifth bit of the idle M-
channel leaving the MTC-20172 SIC in
the LT-T or TE mode is the BUSY bit, see
7.4.
6.6.3.2 Start Of Message (SOM)
and First Byte Transfer
From the idle state, a start of message
transmission is initiated by the sender
with the transition of the MX-bit from
inactive to the active state. The data to
be transmitted are passed in the M-byte
starting in the same frame as the MX-bit
activation.
In normal operation the first byte must
be kept constant in the M-channel until
the SOM is acknowledged by the
receiver.
6.6.3.3 Acknowledge of the
SOM and First Byte
On detection of the SOM, the receiver
will read the M-byte. It will
acknowledge reception, provided that
identical data were seen in the M-
channel during two consecutive frames.
To acknowledge SOM and the first
byte, the MR bit goes from inactive to
the active state, remaining there, until:
1) a next byte is transferred, with MX
indication, see next ;
2) an EOM is signalled by the
transmitter;
3) the receiver wants to abort the
message.
6.6.3.4 Further Byte Transfers
In the case of the second byte transfer,
the sender must detect the transition of
the MR bit of the receiver from inactive
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Fig. 6.12 : SDL Diagram of the M-Channel Transmitter
to the active state (negative edge 1 to
0), before transmitting the second byte,
see previous paragraph.
For subsequent bytes, the sender may
start further byte transmission after
detecting a transition of the MR bit of
the receiver from active to inactive,
(positive edge 0 to 1).
The sender indicates a new byte of
information by the transition of the MX
bit from active to inactive, for exactly
one frame. The data is valid in the same
frame. In the next frame, the MX bit
goes from inactive to active, and the
valid data are repeated. The data are
thus repeated for minimally two frames.
The sender repeats the data in all
subsequent frames until the receiver
returns the MR bit inactive, to
acknowledge the data (see next
section), or to abort the message.
6.6.3.5 Further Byte
Acknowledgement
Each subsequent byte (signaled by MX
going high for one frame, see previous )
is acknowledged by the receiver once it
has seen two consecutive identical bytes
in the M-channel. It acknowledges this
by putting the MR inactive (at 1) for
exactly one frame. In the next frame the
MR bit must go back to active.
6.6.3.6 End of Message (EOM)
Once the sender has received the
acknowledge of the last byte, it changes
the content to FFh, moves the MX to
inactive and keeps it inactive for at least
two frames.
6.6.3.7 Acknowledge of EOM
After the EOM of the sender, the
receiver acknowledges the EOM by
putting MR bit in the inactive state for at
least two frames, keeping it there until
the transmitter goes active again.
6.6.3.8 Sender Not Ready
If the sender is not ready (second byte
or subsequent), the MX bit will be kept
in the active state and the channel byte
stays constant.
6.6.3.9 Receiver Not Ready
If the receiver is not ready for the first
byte, it keeps the MR in the inactive
state.
If the receiver is not ready for the
second byte, it refuses to acknowledge
the bytes by keeping MR in the active
state.
6.6.3.10 IDLE Forced From
Sender
If the first byte is never acknowledged,
i.e. MR staying at 1, the sender can
force the M-channel and MX to IDLE.
If the reception of a subsequent byte is
not (or not yet) acknowledged by the
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Fig. 6.13 : Examples of Received M-Channel Messages
receiver (MR is staying active at 0), the
sender can put the M-channel and MX
to IDLE. The receiver should return MR
to inactive.
The last byte or even the complete
message are never really legally
acknowledged by the receiver.
6.6.3.11 Abort Request From
Receiver
The receiver can abort a message after
the SOM acknowledge or any
subsequent byte acknowledge by
forcing MR inactive for at least two
frames.
The MTC-20172 SIC aborts a message
ONLY when it is forced in HARD RESET.
6.6.3.12 Acknowledge Abort
The sender acknowledges the abort
request by entering the idle state.
6.6.4 Comments on the MTC-
20172 SIC M-transceiver State
Diagrams
The state diagrams for the MTC-
20172 SIC are presented in Figures
6.5 and 6.6.
The receiver oversamples the M-bytes
and considers them valid after two
identical values.
The receiver changes states between the
M-byte reception and the sending of the
outgoing MR bit.
The transmitter changes states
synchronous with the MX, MR reception
and interpretation.
The diagrams are derived from the GCI
standard, with the following
simplification:
- The RECEIVER NOT READY states are
deleted;
- The SENDER NOT READY states are
deleted;
- The receiver and sender work in half-
duplex;
- The outgoing message has priority
over a received message;
- The receiver refuses messages longer
than two bytes; the EOM RX state is
added to the state diagram to
acknowledge a second byte, and to
go to idle followed by a change of the
half-duplex direction, if a message
must be sent;
- The sender sends messages of only
two bytes followed by idle; the EOM
TX state is added to send exactly two
bytes, followed by idle;
- Sender or receiver timeouts are not
implemented.
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Fig. 6.14 : Examples of Received M-Channel Messages
7.1 Introduction
In the MTC-20172 SIC, the M-channel
is used for the transfer of operation
and maintenance information:
1) The TRANSFER of system related
registers (S and Q channel of the
multiframing);
2) The WRITE and READ operations of
internal registers;
- Test and identification registers;
- Mode registers, overriding the
default state, changing the modes
without having to change straps;
- Control registers to change auxiliary
inputs and outputs;
- Status registers, e.g. alarm and error
monitoring;
3) The transfer of the BUSY indication
(TE/LT-T) for the D-channel access is
present in ALL TE/LT-T modes.
M-channel use is not required for
basic mode compatible operation:
In the basic mode, the use of the M-
channel is not necessary. However, it
is available to allow access to the
multiframe S and Q bits, and to
access some internal registers with
additional features.
If the monitor channel is not used, the
MTC-20172 SIC is forced in a default
state after reset, as defined in 7.7.
7.2 M-Channel Receiver
and Transmitter
In the MTC-20172 SIC, the M-channel
transceiver works half-duplex, with
message length 2 bytes. The M-
channel goes to idle after every
message, to allow a change of
direction in the MTC-20172 SIC M-
transceiver. The layer 1 operation of
the M-channel is described in 6.6.
7.3 General Content of
M-Channel Messages
In the MTC-20172 SIC, the M-channel
messages are limited to double bytes.
The first nibble of the message is a
general address, defined in the GCI
standards. In the MTC-20172 SIC this
address nibble must be one of these
values:
0001b, used to access S and Q channel
bits.
1000b, used to read or write internal
registers.
All other values are ignored.
7.4 M-Channel,
Basic Mode
In the MTC-20172 SIC in TE/LT-T, the
M-channel will always contain the
BUSY indication in the downlink M-
channel, see 5.7.3. This happens
during the IDLE and when the channel
is active transferring messages.
The BUSY bit is always present, even
when the Identification Register or the
Version Number Register are transferred.
7.5 S And Q Channel
M-Channel Messages
The MTC-20172 SIC uses double byte
messages to transfer the S and Q bits.
7.5.1 S/Q M-Channel Messages,
MTC-20172 SIC in NT/LT-S With
Multiframing
Downlink
byte 1: 0 0 0 1 1 1 1 1
byte 2: S11 S12 S13 S14 1 1 1 1
Uplink
byte 1: 0 0 0 1 1 1 1 1
byte 2: Q1 Q2 Q3 Q4 1 1 1 1
The downlink messages to the MTC-
20172 SIC contain the S11 to S14
bits.
These bits are sent continuously
downlink on the S-bus via the S-
channel. When the value changes by
an M-channel message, the new
values are put in the S-channel
synchronously with the multiframe. (A
double buffer is used inside the MTC-
20172 SIC).
In uplink direction, the MTC-20172
SIC sends the received Q1 to Q4 bits
each time they change.
7.5.2 S/Q M-Channel Messages,
MTC-20172 SIC In TE/LT-T With
Multiframing
Downlink
byte 1: 0 0 0 1 BUSY 1 1 1
byte 2: S11 S12 S13 S14 BUSY 1 1 1
Uplink
byte 1: 0 0 0 1 1 1 1 1
byte 2: Q1 Q2 Q3 Q4 1 1 1 1
In downlink direction, the MTC-20172
SIC sends the received S11 to S14
bits each time they change. The BUSY
bit is permanently present in the M-
channel.
The uplink messages to the MTC-
20172 SIC contain the Q1 to Q4 bits.
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7. M-Channel Messages and Registers
These bits are sent continuously uplink
on the Q-channel, provided that
multiframing synchronization is found.
When the Q values changes via the
M-channel message, the new values
are put in the Q-channel
synchronously with the multiframe. (A
double buffer is used inside the MTC-
20172 SIC).
7.5.3 S/Q M-Channel Messages,
MTC-20172 SIC Multiframing
Disabled
If Multiframing is not enabled, the
MTC-20172 SIC ignores the content
of the incoming S/Q messages and
will not generate outgoing S/Q
messages. Multiframing enabling: see
5.9.2 and 7.7.3.
7.6 Internal Register
M-Channel Messages
All internal register operations on the
M-channel are double byte messages.
Both READ and WRITE operations are
possible. After every operation, the M-
channel must go idle again.
Concatenation of double byte
messages could result in errors.
Messages which are aborted are
ignored. The MTC-20172 SIC
debounces the different bytes of the
message.
A WRITE operation is a one way mes-
sage, acknowledged only via the MR
bit, see 6.6. However, every register
can be read. A READ operation results
in an answer, delivering the content.
The READ operation causes the two
directions of the M-channel to be logi-
cally dependent! After the READ mes-
sage to the MTC-20172 SIC, the inco-
ming M-channel must return to IDLE.
The M-transceiver in the MTC-20172
SIC gives priority to the delivery of the
CONTENT and/or S/Q messages,
before it can handle the next incoming
(READ/WRITE or S/Q) message.
7.6.1 Write Operation
For a Write operation, the double
byte messages is as follows:
No outgoing message in reaction to
the WRITE.
The second nibble is the address of
the internal register, limited from 1 to
6 in the MTC-20172 SIC. The write
addresses must differ from 0000,
otherwise the READ operation is
assumed.
7.6.2 Read Operation and
Content Message
For a Read operation, the double
byte messages is as follows:
The second nibble is all zero for an
internal READ operation. The fourth
nibble is the address of the register,
from 0 to 6.
The answer is the Content
message, two bytes as follows:
The second nibble is the address of
the internal register, with the BUSY bit
present in TE/LT-T modes.
The second byte contains the content
of the register, again with BUSY
present in the fifth position in TE/LT-T
modes.
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To SIC byte 1: 1 0 0 0 0 0 0 0
byte 2: X X X X X ADR2 ADR1 ADR0
From SIC byte 1: 1 0 0 0 BUSY ADR2 ADR1 ADR0
byte 2: CONTENT (MSB first to LSB last)
To SIC byte 1: 1 0 0 0 X ADR2 ADR1 ADR0
byte 2: CONTENT (MSB first to LSB last)
7.7.1 Identification Register; READ Only; Address 0h
Device I.D. according to the GCI specification.
7.7.2 Version Number Register; READ Only; Address 1h
The version number of the device, starting at 00h.
7.7.3 Configuration Register; WRITE and READ; Address 2h
BT1/SC BT0 : bus type selection in NT/LT-S mode
0 X : bus type according to BUS pin; value at reset;
1 0 : bus type = Adaptive; BUS pin ignored, pin usable as I/O;
1 1 : bus type = Fixed; BUS pin ignored.
SCLK pin (basic mode) disabled in TE/LT-T mode
X3 pin (extended mode) disabled in TE/LT-T mode
0 X : SCLK/XTR3 pin is enabled, basic mode compatible at Reset;
1 X : SCLK/XTR3 is disabled, to simplify clock selection logic.
DEX1 DEX0 : Common Echo Bus mode selection (NT/LT-S)
0 X : DE/CEB bus operates according to DEX pin, value at reset;
1 0 : DE/CEB bus not active; DEX pin ignored;
1 1 : DE/CEB bus driven and sensed; DEX pin ignored.
Busy: READ only bit, present for
compatibility at TE/LT-T. Must be
written at 0, writing BUSY at 1
triggers test-modes.
MFE: Multiframing enable if 1; Reset
value is 0; Enabling is the OR
function of this bit, and other inputs,
see 5.9.2.
LTS/T: Select LTS/T mode in
extended mode; LT-S mode if at 1, LT-
T mode if at 0. After reset put in LT-T
mode, to avoid incorrect behaviour
on multipoint T-bus.
Delt: Delay trimming: compensate
650 ns on the fixed bus sampling in
the NT, and on the TE/LT-T transceiver
roundtrip . Effect identical to the XTR4
pin, see 5.4.3. If both DELT and XTR4
are active the compensation is
doubled to 1300 ns. Reset at 0.
7.7 Detailed Bitmap of the Internal Registers
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I.D. 0 1 1 0 BUSY 0 0 0
V.N. 0 0 0 0 BUSY X X X
CONF BT1/SC BT0 DEX1 DEX0 BUSY MFE LTS/T DELT
Reset 0 0 0 0 0 0 0 0
Ad name sent first sent last
0h I.D. 0 1 1 0 BUSY 0 0 0 READ
1h V.N. 0 0 0 0 BUSY X X X READ
2h CONF BT1/SC BT0 DEX1 DEX0 BUSY MFE LTS/T DELT RD/WR
3h OUT AUX4b1 AUX4b0 AUX3b1 AUX3b0 BUSY TEST AUX1b1 AUX1b0 RD/WR
4h IN1 AUX4 AUX3 ---- AUX1 BUSY MOD2 MOD1 MOD0 READ
5h IN2 (TEST) SCLK XTR4 XTR3 BUSY XTR2 XTR1 XTR0 READ
6h PERF S1/Qb1 S1/Qb2 S1/Qb3 S1/Qb4 BUSY SLIP MFR BER READ
7h TEST device test only; not used in normal operation RD/WR
Table 7.1: Register Bitmap of MTC-20172 SIC
AUXib1 AUXib0 : Configure the AUX4, AUX3 and AUX1 input/output pins
0 0 : The AUXi pin works as listed in 4.11 and 4.12
0 1 : The AUXi pin is tristate and usable as input.
1 0 : The AUXi pin is driven low.
1 1 : The AUXi pin is driven high.
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Busy: READ only bit, present for
compatibility. Must be written at 0,
writing BUSY at 1 triggers test-modes.
Test: Must be written at 0, writing
TEST at 1 triggers test-modes.
(Note: The use of the AUXi pins as
generic inputs of outputs will collide
with their standard use as inputs.
EXAMPLE: one can use AUX1 as
extra output or input. However, the
pin AUX1 has the function DEX in LT-S
modes.
The signal on AUX1 will therefore
enable and disable the DE-bus, unless
DEX is disabled via CONF register.)
7.7.4 Output Register; WRITE and READ; Address 3h
OUT AUX4b1 AUX4b0 AUX3b1 AUX3b0 BUSY TEST AUX1b1 AUX1b0
Reset 0 0 0 0 0 0 0 0
The S1/Qbi bits are the received
multiframe channel bits, sampled
synchronously with the multiframing on
the S-bus.
The BUSY bit is also present here for
compatibility.
7.7.6 Performance Register; READ Only; Address 6h
7.7.5 IN1 and IN2 Registers; READ Only; Address 4h and 5h
SLIP: SET when a slip occurred in LT-
T mode, RESET after being read.
MFR: Indicates Multiframing
synchronization if at 1, in TE/LT-T.
BER: SET each time the BER pin goes
low, RESET after being read.
IN1 AUX4 AUX3 ------ AUX1 BUSY MOD2 MOD1 MOD0
IN2 (TEST) SCLK XTR4 XTR3 BUSY XTR2 XTR1 XTR0
PERF S1/Qb1 S1/Qb2 S1/Qb3 S1/Qb4 BUSY SLIP MFR BER
The bits represent the binary level of
the input pin. All value are sampled
asynchronously at the moment of the
CONTENT message is assembled.
The BUSY bit is also present here for
compatibility.
71
7.8 M-Channel Operation Messages Overview
At reset, the M-channel transceiver is
forced to the idle state. All message
bytes are put to idle, the MX and MR
bits are forced to 1, aborting any
ongoing message.
7.9 Reset of the M-Channel Transceiver
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
To the SIC From the SIC
READ message WRITE message CONTENT mess.
register name Byte 1 Byte 2 Byte 1 Byte 2 Byte 1 Byte 2
Identification 80h 00h -- - 80h content
Version Number 80h 01h -- -- 81h content
Configuration 80h 02h 82h content 82h content
Output 80h 03h 83h content 83h content
Input1 80h 04h (test only) 84h content
Input2 80h 05h (test only) 85h content
Performance 80h 06h -- -- 86h content
Test (test only) (test only) (test only)
S/Q channel -- -- 1Fh S/Q 1Fh S/Q
Table 7.2: M-Channel Message Overview
Overview. Five different types of
test situations are provided for:
8.1 Test of the Device on the Wafer
before Bonding.
8.2 Test of the Single Packaged
Device.
8.3 Equipment Tests, ISDN loop tests,
Acceptance Test.
8.4 System tests, for characterization
of all modes.
The tests outlined in 8.3 and 8.4 are
system tests, performed by the user -
they are not used to test proper device
operation prior to shipment. They are
documented here as a user guide
only.
8.1 Wafer-Test of
the Device
A simplified version of the test for
packaged devices allows a coarse
rejection of defective devices. As this
is used only for initial screening during
production test, it is not specified
further here.
8.2 Packaged
Device Test
Complete RAM and functional test,
using test patterns and a special test
mode in which the device is forced to
speed up the checking.
Beside digital test, the following
functional analog tests are performed
(information only, subject to change):
- The power consumption NT and TE
modes
- The crystal oscillator (start and
range),
- The PLL and DPLL ranges;
- The S-bus Driver amplitudes;
- Receiver and activity detector
sensitivity;
- Receiver AGC.
- Receiver synchronization.
8.3 Equipment Tests,
ISDN Loop-Tests,
Acceptance Test.
These are mainly functional tests,
described here to assist the evaluation
of the device in a real application. A
number of loops and test signals are
used.
8.3.1 Test of the Device on the
Assembled DSP Board
This is a check of the correct
behaviour on the PCB, with more
detailed diagnostics used for
maintenance and repair. Functional
testing of some pins of the device can
be done via the M-channel.
Test-modes can force special signals
on the S-bus: The test signals SSZ,
SCZ, TM1, TM2 can be forced with
C/I commands, or in the NT via
dedicated input pins. The signal level
and frequency correctness of the
assembly can be checked.
In the NT, in is possible to force the
UIC into sending a special test signal,
by giving it the "ei" indication. The
"ei" can be forced as output of the
MTC-20172 SIC (see 6.5.8.2) by
pulling both RSTB and SCZ- (located
at the SCLK pin) low.
Other test can done with functional
loops, either internal or external. An
external functional loop can validate
the complete equipment.
An external loop at the S-bus allows
complete confidence test of the
equipment, including the external S-
bus devices (protection, ...). This
works only in NT/LT-S modes, with the
adaptive bus timing.
The internal loops allow signals (B-
channel and D-channel) to traverse the
digital part and a major part of the
analog part of the MTC-20172 SIC.
If faulty behaviour of the external loop
is found, the internal loops or normal
(half duplex) signal transfers can pin-
point the position of the fault.
In TE mode, no external loop test is
available. The best way to do a
functional test of the MTC-20172 SIC
in TE mode, is to couple it to an
"reference" NT and loop signals at the
NT position. The SIC does not allow
the loop3 test in an EXTERNAL mode.
8.3.2 ISDN Loops and Other
Tests of the Complete
Equipment
The standard CCITT I.430 loop-tests
can be performed, via the command
interface. LOOP2 in NT/LT-S, LOOP3
in TE/LT-T.
To test installed NT/LT-S equipment
including the actual S-bus, the test-
mode Send Continuous Zeros can be
used to force an easily detected 96
kHz on the cabling.
The test signal of the UIC in the NT
can also be forced by pulling RSTB
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8. Loops, Test-Modes, System Tests
and SCZ- pins of MTC-20172 SIC
low. MTC-20172 SIC will send the
"ei" indication to the UIC, which
responds with the test signal.
The BER pin or the BER bit in the
internal performance register can be
used to detect occasional bit errors. In
the NT, this could be a simple LED
indication.
8.4 System Tests, for
Characterization of
all Modes.
To characterize MTC-20172 SIC, a
number of system tests can be
performed:
8.4.1 PLL and DPLLs
All frequencies must be put at maximal
relative ranges. All frequency jumps or
jitter (e.g. XTLI from the MTC-2071
UIC) can be tested.
In LT-T, the correct locking of the SCLK
should be checked, and also the
handling of slip between the local GCI
clock and the S-bus timing.
8.4.2 State Machines of the C/I
Codes
Normal behaviour and incorrect
commands.
8.4.3 M-Channel
Operation of the M-channel
transceiver: MX and MR bits,
protection against single byte errors in
the messages, etc...
Scan and drive of all inputs and
outputs, enabling and disabling all
functions.
8.4.4 D-Channel Access Protocol
Correctness, fairness, advance of the
RDY signal.
8.4.5 Echo Channel and Echo
Bus
Speed of the integrated pull-up. Error-
rate. Correctness in the 22 pin
package version, where the DE and
DEX pins are NOT available, but
active internally.
8.4.6 S-bus Receiver
Complex reflection on all cables in
TE/LT-T short bus.
Adaptive bus timing: Synchronization,
loss of sync.
Fixed bus timing: complex
superposition of signals in NT/LT-S
mode short bus.
Line attenuation range in point-to-
point.
DPLL locking.
Minimal Impedance when no local
VDD on MTC-20172 SIC.
Balanced operation: longitudinal
balance, in the presence of the
disturbing signals specified by CCITT.
E.g. a 200 kHz interfering signal, with
amplitude 100 mVpp (peak to peak)
is applied as specified in CCITT I.430
8.6.2.1.
8.4.7 S-bus Input to Output
(TE/LT-T)
Jitter, delay, operation in multipoint
bus (short bus, extended bus).
8.4.8 Power-down in NT and TE
Power saving. Reliable behaviour
even when GCI bus is not shut-down
according to spec.
8.4.9 Power-up in NT and TE
S-bus Activity detection. GCI bus
activation. No deadlock.
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Related documents:
See chapter 11.
9.1 Absolute
Maximum Ratings
Absolute Maximum Ratings are those
parameter limits above which permanent
damage to the integrated circuit may
occur. It is not implied that more than
one of these conditions can be applied
simultaneously. The maximum ratings
are specified at an ambient temperature
of 25 °C ± 50 °C (unless specified
otherwise) and with ground connected.
- min/max VDD supply voltage,
relative to ground potential.
Min -0.3 V, Max 7.0 V.
- limits for all digital inputs and
outputs:
Max voltage VDD+0.5 V
Min voltage -0.5 V
Max current (Latch-up) 50 mA (at 80 °C)
- maximum power dissipation:
200 mW.
- Storage Conditions:
Temperature should be in the range
-55 °C to 110 °C.
In case of IC deliveries in dry bag,
the conditions of time and humidity
during storage are specified in
Mietec spec 16650.
In case of IC deliveries not in dry bag,
the conditions for a maximum storage
period 2 years are as follows :
Ambient Temperature Relative humidity
(°C) (%)
20 80
30 70
40 60
50 50
During testing, output terminations
shall withstand a short circuit to either
ground or VDD for up to 0.5 second,
with 1 minute between events.
9.2 Transient Energy
Capabilities: ESD
and LATCH-UP
See 10.2.2.
9.3 Thermal Data
The junction to ambient thermal
resistance RthA when mounted on a
horizontal printed board in still air is
less than 60 °C/W for the 22DIL and
90 °C/W for the 28 PLCC package.
The ambient temperature when testing
the device on ATE equipment shall be
raised in function of the test time as to
guarantee the same chip temperature
as on board level at 70 °C ambient.
9.4 Recommended
Electrical Operating
Conditions
Unless otherwise specified, the
characteristic limits for the static and
dynamic characteristics apply over an
operating ambient temperature of 0 to
+70 °C, and for applied voltage
ranges, relative to GND, as follows:
VDD = 5 Volt +/- 5%
IDD = 40 mA max.
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9. Electrical, Physical
and Envir onmental Specifications
See also the related documents,
chapter 11.
9.5.1 Power Supply.
9.5 Static Characteristics.
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SYMBOL PARAMETERS TEST COND. MIN TYP MAX UNIT
VDD power supply S-bus open 4.75 5.25 V
ICC supply current no external load 10 13 # mA
ICC supply current INFO4, 50bus 14 * mA
ICC supply current INFO2, 50bus 18 21 & mA
ICC supply current INFO2, shorted bus 23 28 & mA
ICC supply current power-down, clocks 3 mA
running
ICC supply current power & clock down 0.3 mA
Table 9.1: Static Characteristics of the Power Supply
SYMBOL PARAMETERS TEST COND. MIN TYP MAX UNIT
VIL low level input V 0.8 V
VIH high level input V 2.0 V
IIL low level input
leakage current Vin = 0V -0.01 mA
IIH high level input
leakage current Vin = 5V 0.01 mA
CIN input capacitance 1.1 10 pF
Table 9.2: Static Electrical Characteristics, Digital Inputs
Remark: supply current when
DCLK runs at 512 KHz
# Maximal total supply current = 13
mA, with INFO2 as output signal with
a maximal (100%) mark density,
digital inputs at VDD or VSS, digital
outputs unloaded, S-bus outputs
unloaded.
* To the supply current the S-bus
driver current must be added! Typical
total supply current will be less than
14 mA, during active periods of the
component (RX and TX both ACTIVE),
while sending INFO4, with a normal
(50%) mix of marks and zeros, on the
nominal S-bus impedance.
& INFO2 (= 46 to 48 Marks per S
frame) requires 8 mA ICC, to drive a
7.5 mA differential current in the
nominal impedance of 200
with 1.5
V amplitude (transformed with 2:1
ratio). If the MTC-20172 SIC S-bus
outputs are driving a shorted bus an
output current limitation of 13.3 mA
(worst case) is active and the MTC-
20172 SIC will consume an extra
current of maximally 15 mA.
9.5.2 Static Characteristics Of Digital Inputs.
Digital Inputs are TTL compatible:
9.5.4 Static Characteristics of Analog S-bus Inputs.
9.5.3 Static Characteristics of Digital Inputs.
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PARAMETERS TEST COND. MIN TYP MAX UNIT
DC impedance VDD = 5V ± 5% 350 500 k
DC Input Current indiv. input 10 µA
DC Common Mode V (Output) DC current =0 -5% VDD/2 +5% V
AC Input Impedance VDD = 5V 5% 25 pF
AC Impedance Not powered VDD=0V, note 1 20 k
AC Input V, not powered VDD=0V, note 1 -0.5 +0.5 V
AC Differential Inp. Volt. VSS = 5V 15% 2.6 V
AC Input Voltage Range see note 2 0 VDD V
AC Common Mode rejection see note 3 32 dB
AC Input Voltage Range see note 3 VDD
to reject Common Mode AC indiv. input 1.2 - 1.2 V
AC Input Imped. Mismatch see note 3
Table 9.4: Static Electrical Characteristics, outputs
Internal pull-up resistance
pin name MIN TYP MAX UNIT Presence (para. 3.5)
XTR4 66 100 150 kPermanent
AUX1, AUX3
AUX4, XTR0 33 50 75 kMode Dependent
DOUT 12.5 20 30 kMode Dependent
Table 9.3: Static Electrical Characteristics, pull-up resistors
The current of the integrated pull-up devices must be added to the IIL current.
Note 1: Input voltage range and
impedance when not powered
When the MTC-20172 SIC is not
powered, the AC input voltages are
limited to ±0.5V by the protection
devices of the inputs. External resistance
(typ. 10 k) must be added in series
with each input to limit the current as
discussed under 5.3.3.
Note 2: AC input signal range
The AC S-bus input signal can drive
each individual input to 0V and VDD
provided that no large unwanted com-
mon mode signal is present. Common
mode noise can not be rejected, unless
the limits of note 3 are respected.
The worst case situation happens when
one input would be kept at a constant
DC voltage (with a capacitor) and the S-
bus signals (times the transformer ratio of
1:2) plus the same DC offset are present
on the other input. The input stage sees
the wanted differential signal plus a
common mode signal with half the
amplitude of the differential signal.
(Note that in this case, the S-bus transfor-
mer is also asymmetrically terminated,
which affects the symmetry of the S-bus)
Note 3: AC input signal range
with common mode rejection
The differential input stage is
symmetrical. Therefore, it will reject
unwanted AC common mode noise
signals with 32 dB, provided that each
individual input pin never goes below
1.2V or above (VDD - 1.2V). E.g. an
unwanted 1.1V (peak) common mode
signal added to a wanted 1.5V (peak)
differential S-bus signal will be
sufficiently rejected. Normally the
common mode signal is already
removed to a large extent by the input
transformer and other external devices,
which present a low-ohmic path to
ground or a high series impedance; see
5.3.1.
9.5.5 Static Characteristics Of Analog S-bus Outputs.
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PARAMETERS TEST COND. MIN TYP MAX UNIT
External Series Impedance SIC side 70
Output Impedance MARK on S-bus 20 #
Output Impedance ZERO SIC side 30 * k
Output Not powered (VDD=0V) SIC side 30 & k
Output Current SIC side ± 7.5 ± 13.3 mA
differentially (load imped.:) (200) (0)
Output Voltage on S-bus S-bus 50675 750 825 mV
(magnitude) Fig 5.3 90 100 110 %
Output Voltage on S-bus S-bus 400675 1000 1200 mV
(magnitude) Fig 5.4 90 133 160 %
Open Circuit Output Voltage SIC side 2025 2100 2175 mV
(magnitude) VDD = 5V 135 140 145 %
Table 9.6: Static Characteristics of the S-bus Outputs
PIN PARAMETER DESCRIPTION MIN TYP MAX UNIT
XTLI Tr, Tf Rise and Fall Time 12 ns
XTLI Tp Clock Period 65 ns
XTLI Tw (high) Clock Width High 20 ns
XTLI Tw (low) Clock Width Low 20 ns
XTLO # Tr, Tf Rise and Fall Time 12 ns
XTLO # Tw (high) Clock Width High 55.1 75.1 ns
XTLO # Tw (low) Clock Width Low 55.1 75.1 ns
XTLI/O# frequency Master clock freq. 7.68 MHz
XTLI/O# freq error clock deviation -100 +100 ppm
Table 9.7: Dynamic Characteristics of the Master Clock
# Total impedance of series resistors,
transformer(2:1) + SIC drivers. * External transformer (minimally 2.5
k
) in parallel on the S-bus. & Guaranteed if S-bus differential
signals are below 1.2 V peak.
9.6.1 Master Clock
9.6 Dynamic Characteristics.
# Characteristics at the XTLO output
when the on chip free running crystal oscillator is used. The load
on XTLO is maximum 30 pF.
Dynamic timing parameters are shown in Figures 9.1 to 9.4.
The timing parameters and signal thresholds are shown in Figure 9.1.
The master clock has a nominal period of 130.2 ns.
9.6.2 DCL Output Clock (TE) and
Other Derived Clock Signals
The DCL, SCLK and the other derived
clock signals on pins XTR3, XTR2, and
XTR1 have a duty cycle between 1:2
and 2:1. Among those signals there is
an unknown phase relation. Also the
phase relation of SCLK and XTRi to the
master clock and the GCI clock
signals is not specified or can not
specified.
The jitter on the master clock is
transferred to all the derived clocks.
Moreover, some clocks are locked to
the S-interface as marked with "*" in
4.11, TABLE 9.7. Those clocks will
adjust their periods with one XTLI 7.68
MHz period every 250 µs. The
position of this DPLL adjustment
relative to the S-bus frame or the GCI
frame is not specified. Note that jitter
or width modulation of the 7.68 MHz
XTLI input signal can amplify the DPLL
adjustments on the clocks marked with
"*", which are locked on the downlink
S-bus timing.
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However, the clock period is allowed
to be modulated, as could be needed
to adjust its frequency. In all
applications (NT/TE/LT) the period
can be shortened to as low as 65 ns,
provided that the width (high or low)
never descends below 20 ns.
Note that all jitter on the master clock
is observed on the S-bus transmit
signals, see 5.2.5, and on all other
derived clocks.
PIN PARAMETER DESCRIPTION MIN TYP MAX UNIT
DCLK
SCLK Tr, Tf Rise and Fall Time 20 # ns
XTRi
Table 9.8: Dynamic Characteristics of Derived Clock Signals
# on a 100 pF load capacitance
Fig. 9.1 : Pulse Form of the 7.68 MHz Clock
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9.6.3.1 MASTER Modes
Figure 9.2 shows the timing
parameters of both MASTER modes :
the GCI case and the inverted case.
Fig. 9.2 : GCI Timing Parameters in TE
9.6.3 Serial GCI Interfaces
Figure 9.2 explains the general
behaviour of the signals. Note the
MASTER modes (TE), where the MTC-
20172 SIC generates the DCLK clock
and DFR
frame signals and the SLAVE modes,
where the MTC-20172 SIC receives
DCLK clock and DFR frame.
# bus capacity at 150 pF
& The falling edges are influenced by
the external pull-up resistor in
expended TE mode.
* The rising edge on the Dout pin is
imposed by the external pull-up
resistor in expended TE mode.
PARAMETERS TEST COND. MIN TYP MAX UNIT
TDD Data Delay to Clock# 100 ns
TDD(extended) Falling Data Delay# 100& ns
TDD(extended) Rising Data Delay # xxx* ns
TDF Frame Delay to Clock -20 20 ns
TSD Data Setup Time 20 ns
THD Data Hold Time 50 ns
Table 9.9: Characteristics of GCI Signals, Master modes
## Frame Low Time (GCI ): more than
two DCLK periods. ** Frame Width low (inverted):
nominally one DCLK period. This is
necessary to recognize the modes
automatically.
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9.6.3.2 SLAVE Modes
Figure 9.3 shows the timing
parameters.
Fig. 9.3 : GCI Timing Parameters in NT, LT-Sand LT-T Mode
PARAMETERS DESCRIPTION MIN TYP MAX UNIT
GCI mode
THF Frame Hold Time 30 ns
TSF Frame Setup Time 50 ns
TWF Frame Width (high) 40 ns
TLF Frame Low Time ## ns
Inverted mode
THF Frame Hold Time 50 ns
TSF Frame Setup Time 20 ns
TWF Frame Width (low) 70 ** ns
Table 9.10: Characteristics of GCI Frame, Slave modes
PARAMETERS DESCRIPTION MIN TYP MAX UNIT
TDD# Data Delay, push-pull 100 ns
TDD# Falling Data Delay (open drain) 100& ns
TDD# Rising Data Del.,extern.pull-up xxx* ns
TDD# Rising Data Delay (NT basic mode) 900$ ns
TDDF Data Delay to Frame 150 ns
TSD Data Setup Time 20 ns
THD Data Hold Time 50 ns
Table 9.11: Characteristics of GCI Data, Slave modes
9.6.4 RDY Pin
The timing is discussed in 5.7.5 and
shown on Figure 5.6. The RDY pin
Delay to the GCI DCLK signal is
maximally 100 ns, for a 50 pf load.
9.6.5 ECHO Pin
The timing of the ECHO pin is the
same as the DOUT pin. The ECHO pin
is permanently at 1, except during the
E bits, which coincide with the D-bits
in the GCI frame on the DOUT pin, as
shown on Figure 5.6.
9.6.6 RSTB Pins
Active low for minimally 1 ms.
9.6.7 DE/CEB Bus Timing
The falling edge (open drain) is
maximally 20 ns when loaded with
50 pF. The rising edge is dependent
on the INTERNAL 50 kpull-up
resistor, the number of active SICs on
the DE/CEB bus, the bus capacitance,
and possibly an extra external pull-up
resistor.
Driving and Sensing the DE/CEB bus:
The individual SICs on the DE/CEB
bus pull the bus low when a D-channel
bit at binary 0 is sampled, i.e. a
MARK on the S-bus. The edges on the
bus are related to the internal
sampling clock of the S-bus input data.
Therefore, the absolute timing can not
be specified, as shown on Figure 5.5.
The maximal delay is 1.5µs relative to
the last edge of the D-bit on the SRP
and SRN analog inputs.
Sensing is done during the bit
preceding the E-bit on the S-bus, as
shown on Figure 5.5. All SICs
participating on the bus are sensing
the E-bus and driving the S-bus with a
relative uncertainty of 1520 ns.
9.6.8 BER Pin
The timing of the BER pin is related to
the internal sampling clock of the S-
bus input data. Therefor, the absolute
timing can not be specified. The
falling edge (open drain) is maximally
20 ns when loaded with 50 pF. The
rising edge is dependent on the
EXTERNAL pull-up resistor.
9.6.9 TM1-, TM2-, SCZ-, SSZ-
Pins
Force unconditional state change of
the MTC-20172 SIC to send TEST1 or
TEST2 signal on the S-bus outputs. The
reaction time is depending of the state
of the MTC-20172 SIC S-bus
transceiver, as controlled via the C/I
channel. Reaction times depend on the
activation state of the GCI clock
signals and the presence of the XTLI
signal, or the activation (2ms) of the
crystal connected between XTLO and
XTLI.
9.6.10 The AUX Pins Used As
General Purpose I/O
Signals are driven or sensed
asynchronously via the M-channel
messages, see 7.7.4. Output rise and
fall times 20 ns on 50 pF, if no
(internal or external) pull-up resistor is
present.
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## bus capacitance at 150 pF
& The falling edges are influenced
by the external pull-up resistor in
open drain bus (or multiplexed
modes).
* Rising edge on the Dout pin is
imposed by the external pull-up
resistor when DOUT is open drain.
$ Integrated pull-up resistor in NT
basic mode, clock speed limited
Related documents: See chapter 11.
10.1. Quality
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10. Quality and Reliability Specifications
Test Conditions AQL level Inspection level
Electrical, To product specification at Tamb=25°C 0.15 I
functional and functional and with full temperature range performance
parametric parametric guardband.
External visual Physical damage to body or leads. 0.15 II
Dimensions affecting PCB
manufacturability such as bent leads,
coplanarity,...
External visual Correctness of marking. All other 0.65 II
major defects.
Test Conditions Acceptance criteria
Hermeticity Fine leak AQL 0.40 IL II
(only for cavity packages
such as CLCC, SB, PGA,...)
Hermeticity Gross leak AQL 1.00 IL II
(only for cavity packages
such as CLCC, SB, PGA,...)
Solderability T=245 °C, min 95% 0 rejects on sample
wetting of terminations. of 5 per package type
Meniscography per week.
10.1.3 Assembly monitor
Assembly related product conforman-
ce is guaranteed by means of:
- the quality system of the assembly
subcontractor
- incoming inspection on assembled
material
- the IQA (incoming quality
assurance) function including
subcontractor audit
- the assembly monitor as specified in
Table 10.2.
Table 10.1: Acceptance Criteria
Table 10.2 : Assembly Monitor
10.1.1 Product acceptance tests
10.1.2 Lot-by-lot acceptance test
Lot conformance to specification of
products delivered in volume production is guaranteed by means of
following tests:
All products are tested 100 %, at
ambient temperatures with full
temperature range performance
guardband, by means of production
test programs that guarantee optimal
coverage of the product specification.
10.1.4 Delivery lot Certification
Each delivery lot to be accompanied by
a Certificate of Conformance
10.1.5. Quality System
A quality system with certification
against ISO9001 is maintained.
10.2 Reliability
Specification
In order to guarantee the specified
reliability, Mietec performs a product
qualification for each product. In order
to minimize reliability testing, structural
similarity is applied. This qualification
procedure together with the application
of structural similarity is described in the
Mietec specification documents 15501,
15502, and 15503.
10.2.1 The Intrinsic Failure Rate
When used under benign conditions
and a junction temperature of 50 °C,
the failure rate will not exceed :
- 1000 ppm during the first year in the
field
- 100 FIT or ppb/hour after the first
year (long term failure rate)
Expected early failure rate is below
100 ppm.
Failures due to external overstress such
as ESD, voltage and current overstress
(e.g. due to EMI), mechanical and
thermal shocks, ... are not included in
these Figures.
10.2.2 External Stress Immunity
- Electrostatic discharge : The device
withstands 1000 Volt Standardized
Human Body Model ESD and 250
Volt CDM pulses when tested
according to Mietec spec 15951.
- Latch-up : Static latch-up protection
level is 50mA when tested according
to JEDEC no. 17.
10.2.3 The Useful Life
The useful life, when used under
moderate conditions, is at least 20
years. The term useful life is specified as
the point in the lifetime, where the
intrinsic failure rate exceeds the long
term failure rate specified under 10.2.1
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11.1 Related Documents
(1) MTC-20172 SIC Advance Information sheet, DS0139c.
(2) MTC-2072 UIC Data sheet and user manual.
(3) ISDN Application note - CCITT LAPD. AN0148a
(4) GCI interface, Industry standard bus, description agreed by Siemens,
Alcatel, Plessey and Italtel. Evolution of the Siemens IOM-1 (trademarked),
and later further enhanced to Siemens IOM-2 (also trademarked).
(5) "Mietec Packaging Handbook" PB026a, and specification number 16505
(6) "Standard Marking specification", specification number 16020
11.2 Other Documents
(1) CCITT Recommendation I.430 Edition 5/86, blue book, plus updates for the
subsequent releases.
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11. Related Documents
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12. Application note for ETS-TM3 Qualification
12.1 Scope
This application note describes results
of consultancy tests done at a
qualified lab to perform ETSI-TM3
ISDN layer 1 conformance tests. A
number of electrical tests specified in
these conformance tests are sensitive
to the SIC, external transformer and
series resistances. Results will be given
for a number of transformers. Also a
number parameters will be given to
setup a number of variables for the
TM3 qualification.
12.2 External Circuit
See figure 12.1
12.3 ETSI-TM3
Configuration
Setup
In order to pass succesfull the
conformance test procedures a
number of device dependant
parameters mst be set :
Fig. 12.1 : MTC-20172 SIC external circuity
12.3.1 Network Terminations (NT)
12.3.2 Terminal Equipments (TE, LTT)
Use a range for PX M; ................................False
Frame Regain Frames (PX M) ...................6
Use a range for PX N: .................................False
Frame Loss Frames (PX N) .........................2
Sendix Frame Type: ......................................IX-96KHz
12.4 Qualification Results
Results will be shown for the pulse tem-
plate tests and input and output impe-
dance tests. The LCL test is not mentio-
ned in this application note because it
strongly depends on board layout and
housing of the equipment. Following
configurations have been measured :
12.4.1 Transformer VAC ZKB505/105
12.4.1.1 Output pulse Template for 50
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Fig. 12.2 : Output pulse template for 50
Transformer Transmitter series MTC-20172 version
resistance
VAC ZKB505/105 2 x 34FICA_OAB
12.4.1.2 Output Pulse Template for 400
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Fig. 12.3 : Output pulse template for 400
12.4.1.3 Output Impedance Power off State
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Fig. 12.4 : Output impedance State_F1
12.4.1.4 Output Impedance Power on State
Fig. 12.5 : Output impedance State_F1
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12.4.1.5 Input Impedance Power off State
Fig. 12.6 : Input impedance State_F1
12.4.1.4 Input Impedance Power on State
Fig. 12.7 : Input impedance State_F1
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13. Application Note Network Terminator
13.1 Scope
This application not describes how to
use the MTC-20172 in a network
termination (NT) configuration. Also
recommendations are given for the
choice of external components in the
receive and transmit path.
13.2 NT Mode with
MTC-2071 4B3T UIC
13.2.1 Schematic Diagram
See figure 13.1
Fig. 13.1 : MTC-20172 SIC in NT mode with MTC2071 UIC
see Figure 2
Fig. 13.2 : MTC-2071 UIC - recommended Hybrid and Transformer configuration
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13.2.2 Description
Atthesubscriberpremises,the2–wire
U–interface is terminated by a UlC in
NT–mode. This UIC is connected to
the SIC in NT- mode via the serial
interface, to provide a 4–wire
So–interface.
The SIC receives its clock from the UIC
via the pin CLS. This clock (7.6BMHz)
is synchronous to the received data at
the U–interface and is derived from
the master clock at the central office.
A number of pins can be strapped
either to O or 1:
Pin Value Description
SCLK 0 Switch on SCZ (send continuous zeros) testmode
1 No action
XTR3 0 Adaptive timing for point to point mode
1 Fixed timing for short passive bus mode (<200m)
XTR2 0 Switch on SSZ (send single zeros) testmode
1 No action
The device is initialized when the pin
RESETB is held low. It is necessary to
reset the device after the power is
supplied to VDD. There commended
time to keep RESETB low is 1 ms
after VDD reaches 5V.
The device is delivered in a 22DIL or
28PLCC package. There are a
number of pins only used in the
28PLCC package. The pins XTR4,
AUX1, AUX3 and AUX4 can be left
unconnected if the functionality is not
needed. We recommend to connect
the pin VDD(pin28) to the 5V power
supply and the pin AUX(pin25) to the
OV power supply.
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13.3 Requirements for the Input and Output Stage
In the receive path the So-interface is
terrninated with 50(1 00in the
NT and 1 00at the end of the So-
bus). The input stage of the MTC-
20172 SIC is fully differential.
A capacitance to ground as in the is
not necessary and should be removed
to benefit the higher immunity to
common mode signals. The path also
must contain 2 series resistances of
5Kto fuKil the CCITT 1.430 input
impedance requirement. Protection
circuitry must be present after the
secondary of the transformer to make
sure the SRP and SRN pin are not
stressed higher than VDD+0.6V or
lower than VSS-0.6V.
To fulfill the CCITT 1.430 requirement
that the transmitter impedance must be
20seen at the So-interface
(so 80seen at the secondary of the
1:2 transformer). To fuifil the CCITT
1.430 pulse amplitude requirement of
750mV over 50at the So- bus, the
MTC-20172 SIC driver has been
designed as a current limited voitage
source of 2.1V. With an extra series
resistance of 80in the transmit path
both CCITT 1.430 requirements are
met. The series resistance includes the
transformer primary and secondary
series resistance and the resistance of
the connecting cord. A vaiue of
2x34is recommended for the
external resistors. Protection circuitry
must be present after the secondary of
the transformer to make sure the SXP
and SXN pin are not stressed higher
than VDD+0.6V or lower than VSS-
0.6V.
Fig. 13.3 : Schematic of MTC-20172 input and output stage
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02/97 - DS 0209b
This document contains information on a new product.
Alcatel Mietec
reserves the right to make changes in
specifications at any time and without notice.
The information furnished by
Alcatel Mietec
in this
document is believed to be accurate and reliable.
However, no responsibility is assumed by
Alcatel
Mietec
for its use, nor for any infringements of patents or
other rights of third parties resulting from its use.
No licence is granted under any patents or patent rights
of
Alcatel Mietec
.
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Representatives
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MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997