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DS1-BD (DS1 Interface Circuit Pack)
Issue 1 June 2005 1031
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. The test runs only if the 120A CSU module/
T1 sync splitter is present, administered, and connected to a 1.544-Mbps TN767E DS1 circuit
pack on the back of the port carrier.
The test is destructive and can only be initiated by test ds1-loop location ds1/
csu-loopback-test.
Use busyout board to busy out all trunks or ports on the DS1 Interface circuit pack before
running the RLB test.
When the RLB test is initiated, maintenance software sends a message to the TN767E DS1
Interface circuit pack to start the test. The board sets up the RLB loop back, transmits a test
pattern, and verifies that the pattern is received unaltered through the loop back. If the
transmitted and received pattern is different, the test fails.
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, use release board to restore all trunks or ports on the TN767E
DS1 Interface circuit pack to the in-service state.
Table 355: Test #1211 CSU Repeater Loop-Back Test
Error
Code
Test
Result
Description / Recommendation
ABRT Internal system error
1. Retry test ds1-loop location ds1/csu-loopback-tests at
1-minute intervals up to 5 times.
1005 ABRT CSU Repeater Loopback test cannot be executed in the current
configuration.
1. Use change ds1 location and set the Near-End CSU Type field
on the DS1 circuit pack administration screen to integrated, and/or set
the Bit Rate field to 1.544 if the board is to be used in a 24-channel
configuration.
2. Retry test ds1-loop location ds1/csu-loopback-tests.
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