Maintenance

4-19

3160-A2-GB21-80 March 1999
Test Commands
The test commands enable you to run loopbacks and test patterns on the
DSU/CSU, and to test the front panel LEDs. These tests can help you isolate
areas of trouble if you are having problems with your DSU/CSU.
To access all Test commands from the Test branch, press F2 to select Test from
the top-level menu screen.
F1
DSU ESF
Stat Test Cnfig
F2 F3
Remote Loopback Tests
The Remote Loopback tests enable you to troubleshoot your circuit by sending
the following to a far-end device:
For Networks
Line loopback up activation sequence for 10 seconds (LLBUP)
Line loopback down activation sequence for 10 seconds (LLBDN)
For Channels
V.54 activation sequence to initiate a V.54 Loop 2 (54UP)
V.54 deactivation sequence to terminate a V.54 Loop (54DN)
ANSI T1.403 (Annex B) activation sequence to initiate a DCLB on the remote
device (FT1UP)
ANSI T1.403 (Annex B) deactivation sequence to terminate a DCLB on the
remote device (FT1DN)
You cannot perform remote loopbacks if any of the local loopbacks are active. If
you attempt to do so, the error message Invld Test Combo (Invalid Test
Combination) appears.
NOTE:
The following procedures are examples only. Screen displays may vary
depending on the model and configuration of the DSU/CSU.