9500 MXC User Manual
3DB 23063 ADAA - Rev 004 July 2007 Vol. VI-A-23
3. Leave a BER test on overnight (or other specified period) to confirm
error-free ring operation.
• If a BER test shows errors, cross-check against the G.826 stats in the
Performance screens for all nodes in the ring.
In all but exceptional circumstances, such as a DAC failure, BER test errors
will correlate with radio link errors in G.826 performance stats. Check the
affected link to determine the cause of errors. Checks should include
reference to path conditions, which may indicate a path-fade problem.
Where G.826 performance data is error-free on all ring links, the presence
of BER test errors indicates a problem within one of the DACs and/or its
interfacing to the RAC via the TDM bus. Check other tribs and use local
digital and IF loopbacks to help isolate the problem.
Confirming Ring Wrapping and Unwrapping
Ring wrapping will occur when one or more links in the ring fail.
For ring-wrapping criteria for radio (RAC/ODU) and fiber (DAC 155oM) ring
refer to:
• Radio Links on page A-23
• Fiber (DAC 155oM) Links on page A-24
• Wrap and Unwrap Times on page A-24
• Checking Wrap and Unwrap Operation on page A-25
Radio Links
Conditions for ring wrapping:
• Tx path failure:
• Tx synthesizer not locked
• Tx transceiver failure
• Tx power failure
• Tx ODU IF synthesizer not locked
• Tx RAC IF synthesizer not locked
• Modulator not locked
• Rx path failure:
• Rx synthesizer not locked
• Rx IF synthesizer not locked
• Demodulator not locked
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