Avaya S8700 Series, Maintenance Manual

Page: 1359 / 2618

DS1-BD (DS1 Interface Circuit Pack)
Issue 1 May 2002 8-637 555-233-143
CSU Repeater Loop-Back Test (#1211)
This test is destructive.
The CSU RLB (Repeater Loopback) test causes a loop back at the far-edge of the
local 120A CSU module or T1 sync splitter, and tests the connection from the
TN767E DS1 board to and including the CSU module/T1 sync splitter circuitry.
This test will only be performed if the 120A CSU module/T1 sync splitter is
present, administered, and connected to a 1.544-Mbps TN767E DS1 circuit pack
behind the port carrier.
The test is destructive and can only be initiated by a technician demanded
test ds1-loop UUCSS ds1/csu-loopback-tests command.
All trunks or ports on the DS1 Interface circuit pack must be busied out via the
system technician busyout board command before running the RLB test.
When the RLB test is initiated, maintenance software sends an appropriate
message to the TN767E DS1 Interface circuit pack to start the test. The board will
set up the RLB loop back, transmit a test pattern, and verify that the pattern is
received unaltered through the loop back. If the transmitted and received pattern
is different, the test fails.
In addition, the DS1 circuit pack hardware applies a DC current while the test is
running in order to detect any broken wires that may not be detected by the
loop-back pattern.
When the test is complete, all trunks or ports on the TN767E DS1 Interface circuit
pack are restored to the in-service state after the release board command is
entered.