WorkCentre Pro 423/428
2-102
CHAPTER 2 TROUBLESHOOTING
03/02
Level 2 Troubleshooting
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S/T
point
An S/T point is a connection point between devices connected to an ISDN line. The
connection points are named U, T, S, and R sequentially from the network side. The names
represent mere connection points but not physical things.
Device
Description
Actual example
NT1
Network terminating device (when viewed from the office
side) realizing power feed and other functions
DSU
NT2
Device with line switching and concentration functions
PBX, etc.
TE1
ISDN terminal with I interface
G4 Fax, etc.
TA
Adapter to connect a non-ISDN terminal to ISDN
TA/router, etc.
TE2
Conventional terminal with no I interface (Non-ISDN
terminal)
G3 Fax, etc.
NT1 (DSU) is an essential device but the other devices are combined depending on the
status as follows:
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NT1+NT2+TE1 (above connection example 1)
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NT1+NT2+TA+TE2 (Connection example 2)
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NT1+TA+TE2 (Connection example 3)
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NT1+TE1
An S/T point indicates a connection point between NT1 (DSU) and TE1 or TA when there is
no NT2 (PBX). In NET64, T and S indicate the same connection point because NT2 is
usually not used. Then the point is expressed as S/T.
The U, T, S, and R points indicate the demarcation points of responsibility about each
terminal. They also define the ranges of responsibility for maintenance.
The U point is the demarcation point between the class-1 carrier and user. NET64 uses a
two-core cable (NET1500: optical cable) from the network to NT1 (DSU) and a four-core
cable of RJ45 from NT1 to TE1 or TA.
A TA/router with built-in DSU has NT1 and TA in one cabinet but allows TE1 (ISDN terminal)
connection by taking the S/T point outside. A model with no S/T point allows only TE2
connection. A router supporting an S/T point may have a built-in DSU.
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Bus
wiring
Bus wiring is used to connect several terminals to an ISDN line. The figure below shows this
wiring. Two pairs of twisted-pair wires are used to make the polarities (TA, TB, RA, and RB)
common between DSU and all connection blocks.
Since the polarities of wiring screws in a connection block may be different, check the pin
numbers of RJ45 before wiring.
For bus wiring, note the distance from DSU to the farthest terminal.
Short-distance bus connection (terminals at random intervals on a bus): 150 m max.
Long-distance bus connection (all terminals centralized within 50 m on a bus): 550 m max.
Since the ISDN cable between a connection block and a terminal is not stranded (paired-
wire), do not use a long cable beyond 4 meters.
RA
RB
TA
TB
RB
TB
RA
TB
RB
RA
TA
TA
RJ45 Connection
block pin No.
D
S
U
Use twisted-pair
Pin8 … 1
6
Terminator
Connection
example 1
U
point
NT1
NT2
TE1
NT1
NT2
TA
TE2
NT1
TA
TE2
S/T point
Network side
4-core cable
T
point
S
point
R
point
Connection
example 2
Network side
T
point
S
point
Connection
example 3
Network side
R
point
U
point
U
point
2-core cable
Summary of Contents for WorkCentre Pro 423
Page 2: ......
Page 3: ...WorkCentre Pro 423 428 6HUYLFH 0DQXDO...
Page 6: ......
Page 8: ......
Page 9: ...INTRODUCTION...
Page 10: ......
Page 24: ...WorkCentre 423 428 03 02 INTRODUCTION 14 7 Translation of Warnings...
Page 25: ...CHAPTER 1 SERVICE CALL PROCEDURE...
Page 26: ......
Page 28: ...WorkCentre Pro 423 428 1 2 CHAPTER 1 SERVICE CALL PROCEDURE 03 02 1 1 Trimming...
Page 31: ...CHAPTER 2 TROUBLESHOOTING...
Page 32: ......
Page 76: ...WorkCentre Pro 423 428 2 44 CHAPTER 2 TROUBLESHOOTING 03 02 2 3 Level 2 Troubleshooting...
Page 243: ...CHAPTER 3 IMAGE QUALITY TROUBLESHOOTING...
Page 244: ......
Page 273: ...CHAPTER 4 DISASSEMBLY ASSEMBLY AND ADJUSTMENT...
Page 274: ......
Page 329: ...CHAPTER 5 PARTS LIST...
Page 330: ......
Page 415: ...03 02 5 2 Parts List WorkCentre Pro 423 428 5 85 CHAPTER 5 PARTS LIST...
Page 416: ...CHAPTER 6 GENERAL...
Page 417: ......
Page 456: ...CHAPTER 7 ELECTRICAL WIRING DIAGRAMS...
Page 457: ......
Page 476: ...CHAPTER 8 ACCESSORIES...
Page 477: ......
Page 535: ...WorkCentre Pro 423 428 8 58 CHAPTER 8 ACCESSORIES 03 02 8 22 Stamp Kit Red...
Page 536: ...CHAPTER 9 BSD Block Schematic Diagram...
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