5.5 Data Transfer Is Badly Corrupted
If data transfer in one or both directions has high error rates, the problem is
most likely inadequate optical signal strength, caused by either (a) foreign
matter in a fiberoptic interface, (b) low optical power output of one or both
optical transmitters, (c) inadequate sensitivity of one or both optical receivers,
or (d) damage to the fiberoptic cable resulting in excessive optical-signal
attenuation.
Before doing anything else, check (and clean if necessary) the cable’s
connectors and the muxes’ transmitter and receiver, as described in the
second paragraph of the previous section. If the high error rate remains after
cleaning:
If the high error rate hits data transmitted in one direction but not data
transmitted in the other direction, the cause of the problem can be isolated
by reversing the fiberoptic cable connections at both multiplexors as
described in Step 3 of the previous section. If, when you do this, the direction
of the high error rate reverses, the problem is in the cable. If the direction of
the high error rate does not reverse, the problem is in one of the
multiplexors.
If the high error rate hits both directions of data transmission, try swapping
in another fiberoptic cable as directed in Step 4 of the previous section. If the
problem goes away when you use the replacement cable, the old cable is
faulty.
If the problem remains and you have an optical power meter, test the
fiberoptic components as described in the third paragraph of the previous
section. If an optical power power is not available, call us for technical
support.
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CHAPTER 5: Troubleshooting
