Description of the problem

Single station OSN3500 PQ1 first 2M channel to do unidirectional crossover, 2M BER meter test about 15 minutes after the report of the error code, forced TPS inversion continue to test still report the error code, the network management is no abnormal alarms.

Alarm Information

No

Processing

1. Apply for spare parts of PQ1 single board, replace it and continue to hang the meter for testing, the meter still reports an error code.

2. Replace the 33rd 2M channel, test under the same conditions, continue to report error codes, initially exclude cable problems.

3. single-station branch board to do the outer loop, hanging meter test 15 minutes, no error code reported.

4. suspect that the meter itself has a problem, after checking the meter before the transmit clock mode is "internal clock", change to "receive clock" mode to continue to hang the meter test, the meter no longer reported BER.

Root cause

Insufficient accuracy of the internal clock of the test instrument, and the clock between the network element and the instrument is not synchronized, resulting in the generation of erroneous codes.

Solution

If the instrument supports clock mode setting, set the transmit clock mode to "receive clock" to avoid the internal clock precision is not enough, resulting in the generation of error codes.

Suggestion and summary

If the 2M instrument supports clock mode setting, set the transmit clock mode to "receive clock" to avoid the internal clock precision of the instrument is not enough, which leads to the generation of error codes during the test.

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