Method 2: Loopback Test On Each Fiber Of The Duplex Cable - HP 27115A Installation Manual

Method 2: Loopback Test on Each Fiber of the Duplex Cable
The second method to test the cable can help to determine if a marginal
transmitter or receiver on the PCA exists. It presupposes that the remote end of
the duplex cable can be physically connected to the HP-FL peA. This may not be
possible depending on the location of the remote device, or the medium through
which the duplex cable is run.
To conduct this test, do the following (we assume that you have already tested
the HP-FL peA using the instructions provided earlier):
1. Remove the duplex cable from the remote device. (Refer to the
applicable device manual.)
2. Identify one of the duplex cable fibers, and its corresponding
connectors at each end. Duplex fiber-optic cables are normally marked
to allow easy identification of each fiber. (See the section in chapter 2
titled "Connect the Fiber-Optic Cable".)
The remaining procedure assumes the hookup is correct.
3. Connect each end of the fiber to the HP-FL peA (transmit port and
receive port, respectively) so that the fiber acts as a loopback cable.
4. Run the peA self-test (refer to "PCA Fault Isolation", above).
5. Observe the PCA LEDs. The self-test fail LED should turn off, indicating
the peA is good.
If the S or R LED now turns on, the fiber is probably faulty, and the
cable s1¥>uld be replaced. (Again, the peA'S transmitter/receiver may
be marginal.)
6.
If the Sand R LEDs remain off, the fiber is good, and you should repeat
the process on the other fiber (starting at step "3" above).
7.
If both fibers pass the test, the duplex cable is not faulty, and the peA's
transmitter and receiver appear to be good. Test the remote device.
3-12 Troubleshooting and Diagnostics