27 — Loopbacks
27-8
2902 MainStreet Technical Practices
90-2906-01 May
2002
Loopback B for two-port DTUs
For two-port DTUs, loopback B is a bidirectional loopback that can be initiated on
either Port A or Port B (see Figure 27-7). The signal from the Control card is looped
back within the DTU in the DRAGA chip, on the side closest to the DNIC module.
The signal from the data device is looped back in the DRAGA chip also, but on the
inside of the DRAGA.
Figure 27-7 Loopback B for two-port DTUs
Loopback B for eight-port DTUs
For eight-port DTUs, loopback B is a bidirectional loopback that can be initiated
from either circuit A or B (see Figure 27-8). The signal from the Control card is
looped back within the DTU inside the DRAGA chip. The signals from the data
devices connected to the selected aggregate port are looped back on the side closest
to the DNIC module.
8852
2902 MainStreet
DNIC
module
Control
card
DX
DNIC
line driver
DTU
DRAGA
Loopback B
Data
device
DRAGA
Summary of Contents for MainStreet 2902
Page 1: ...2902 MainStreet Network Termination Unit Release 1 0 H T E C H N I C A L P R A C T I C E S ...
Page 40: ...3 Mounting the unit 3 8 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 50: ...4 Ground and power connections 4 10 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 68: ...6 Connecting to the network 6 4 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 90: ...7 Connecting to data devices 7 22 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 108: ...10 Node management 10 10 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 150: ...14 CPSS 14 6 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 218: ...20 Codirectional DCM 20 6 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 234: ...22 HCM rate adaption 22 10 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 246: ...23 Cross connecting circuits 23 12 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 254: ...24 Visual indicators 24 8 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 266: ...25 Alarms 25 12 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 278: ...26 System diagnostics 26 12 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 298: ...27 Loopbacks 27 20 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
Page 332: ...Glossary GL 8 2902 MainStreet Technical Practices 90 2906 01 May 2002 ...
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Page 344: ... 2002 Alcatel All rights reserved 90 2906 01 95 1820 01 00 C ...