Avaya S8700 Maintenance Manual page 598

Maintenance Object Repair Procedure
Far CSU Loop-Back Test (#1213)
This test is destructive.
The Far CSU Loopback (R-LLB) test causes a loopback at the far-end CSU and
tests all circuitry and facilities from the local DS1 board to the far-end CSU.
The test is destructive and can only be initiated by a technician-demanded test
ds1-loop UUCSS far-csu-loopback-test-begin command.
Every trunk or port on the UDS1 Interface circuit pack must be busied out using
the system technician's busyout board command before running the Far CSU
Loopback test.
If the far-end CSU is not a 120A1 CSU module, and the DS1 is administered for
ami-zcs line coding, density protection must be disabled on the CSU during the
test due to the large number of zero's in the 3-in-24 test pattern.
The Far CSU Loopback test has the UDS1 Interface circuit pack transmit a
loopback activation code to the remote CSU, waits up to 15 seconds for return of
the code to verify the loopback has been established, transmits a framed 3-in-24
test pattern, begins counting bit errors in the received test pattern, and returns a
PASS result. If the loopback is not established within the 15 seconds, the test
fails.
The status of the Far CSU Loopback test is available in the hardware error log via
Error Type 3901. Several distinct Aux values give the user information about the
status of the test.
The list measurements ds1 summary command will display the length of time
the test has been running (Test Duration field) and number of bit errors
detected (Loopback/Span Test Bit-Error Count field). If the test pattern
is being passed through the loopback cleanly, the number of bit errors should be
very low. The command will also display the type of Loopback/Span test
executing (Test field), the type of pattern generated for the type of
Loopback/Span test (Pattern field), and whether the pattern (i.e., 3-in-24
Pattern) is synchronized (Synchronized field).
To terminate the test, enter the test ds1-loop UUCSS end-loopback/span-test
command or the release board command. Using the release board command
will restore every trunk or port on the UDS1 Interface circuit pack to the in-service
state.
8-1294 Issue 1 May 2002 555-233-142