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MULTIMODE FOMS -ST AND -SMA
C. Perform a BERT (bit error rate) test on each FOM. If the BERT test
doesn’t uncover any faults, but the RS-232 device still indicates a fault,
follow the manufacturer’s suggested diagnostic procedures for the
RS-232 device. Also, check the cable between the RS-232 device and the
FOM.
5.3.2 R
EMOTE
L
OOPBACK
The remote loopback test checks the performance of both the local and
remote MultiMode FOMs, and the communication link between them. Any
characters sent to the remote FOM in this test mode will be returned to the
originating device. For example, if your local RS-232 device is a terminal,
characters typed on the terminal’s keyboard will appear on the terminal’s
screen after having been passed to the remote FOM and looped back.
To perform a remote loopback test, follow these steps:
A. Activate remote loopback by moving the remote MultiMode FOM’s
front-panel toggle switch
up
to the “Remote” setting: this FOM now
automatically echoes data back across the fiberoptic line to the local
FOM. The remote unit’s “Test” LED should glow. (As with the local
loopback test, the synchronized connection between the two modems
remains intact during this test.)
B. Perform a BERT (bit error rate) test on the system.
C.If the BERT test equipment indicates a fault, and the local loopback test
was successful for both MultiMode FOMs, this suggests a problem with
the fiber cable connecting the modems. You should test the cable for
proper connections and continuity.
5.4 Power-Down
To turn off the MultiMode FOM, unplug its power supply from the outlet.
The FOM has no power switch.
