Bert Test; Ring Integrity Test (Master Fault Tolerant Mode) - Optelecom 9525A Installation And Operation Manual

3.3 BERT Test

The unit has a rudimentary BERT test feature that may be implemented off-line. See section 2.3.6 for
additional information. While the test is being run, no other signals may be introduced to a modem in
the network. To run the test, set either switch #3 (for TX1 source), or switch #4 (for TX2 source) of
the MODES dipswitch DOWN. The BERT indicator will illuminate on all modems properly receiving the
signal for presentation at the RD output. It will not illuminate if the data is only being repeated but not
dropped off (via RD) by the modem. If initiated from the master in a fault tolerant ring and the BERT
LED on the master illuminates, it is receiving data that has traveled around the ring. To test each ring
separately, selectively enable the TX11 or TX2 BERT signal outputs and confirm that the BERT LED
illuminates in both cases.

3.4 Ring Integrity Test (Master Fault Tolerant Mode)

When in Master Fault Tolerant Mode, the Fault LED will illuminate and the ALARM relay will activate if a
transmitted burst is not being transmitted around both rings and received by BOTH optical input ports.
If it is not received by one of the inputs, it indicates a break in that ring possibly caused by a broken
fiber or a failure of one of the modems on the ring. If this happens, disconnect the good fiber input
and enable the BERT test. Go around the ring to see which modems have the BERT LED illuminated.
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