Avaya S8700 Maintenance Manual page 1367

DS1-BD (DS1 Interface Circuit Pack)
Far CSU Loop-Back Test (#1213)
This test is destructive.
The Far CSU Loopback (R-LLB) test causes a loop back at the far-end CSU and
tests all circuitry and facilities from the local TN767E 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.
All trunks or ports on the DS1 Interface circuit pack must be busied out via the
system technician busyout board command before running the Far CSU
Loopback test.
If the far-end CSU is not a 120A CSU module or a 401A T1 sync splitter, and the
DS1 is administered for ami-zcs line coding, one's 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 TN767E DS1 Interface circuit pack transmit a
loop-back activation code to the remote CSU, waits up to 15 seconds for return of
the code to verify the loop back 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 loop back is not established within the 15 seconds, the test
fails.
The status of the Far CSU Loopback test will be available in the hardware error
log via Error Type #3901. Several distinct aux values will be used to give the user
information of 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 loop back cleanly, the number of bit errors should be
very low. The command will also display the type of loop-back/span test
executing (Test field), the type of pattern generated for the loop-back/span test
(Pattern field), and whether the pattern (i.e., 3-in-24 Pattern) is synchronized
(Synchronized field).
To end the test, enter test ds1-loop UUCSS end-loopback/span-test or the
release board command. Using the release board command will restore all
trunks or ports on the TN767E DS1 Interface circuit pack to the in-service state.
555-233-143 Issue 1 May 2002 8-645