27 — Loopbacks
2902 MainStreet Technical Practices
27-3
May 2002 90-2906-01
Figure 27-1 Loopback types
For bidirectional loopbacks, the transmission path is interrupted and the signal is
looped back to both ends of the connection.
For unidirectional loopbacks, the transmission path is interrupted and the signal is
looped back in one direction only.
For unidirectional loopbacks with pass-through, the transmission path is interrupted
and the signal is looped back to one end and passed through to the far end.
Loopback indicators
Primary rate loopback LEDs on the Control card (see section 24.3) indicate that the
2902 MainStreet system is running a primary rate loopback.
When a loopback is in progress for a circuit, the circuit status has “-M” (for
maintenance) appended to it.
Procedure 27-1 To remove a specific loopback
MAINT — ON_CIRCUIT — <
pp-c
> or <P
p-c
>
↵
— UNDO_MAINT
where
pp
is 1 or 9,
c
is 1, 2, A or B
p
is 1 or 2,
c
is 1 to 31
Procedure 27-2 To remove all loopbacks
MAINT — UNDO_MAINT
The UNDO_MAINT softkey only appears when one or more loopbacks are set.
27.2
2B1Q circuit loopbacks
2B1Q modules support remote connection of data devices through 2700 MainStreet
series DTUs.
Bidirectional loopback
Unidirectional loopback
Unidirectional loopback
with pass-through
3622
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 ...
Page 343: ......
Page 344: ... 2002 Alcatel All rights reserved 90 2906 01 95 1820 01 00 C ...