CANOGA PERKINS 2270 Fiber Optic Modem - Manual (Page 58)

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Canoga Perkins
Chapter 6 - Diagnostic Procedures
6.1 2270/2201 Diagnostic Procedures
The following diagnostic procedures should be followed to test the 2270 system, troubleshoot a
defective link or detect a defective fiber optic cable, connector, modem or power supply.
NOTE: Refer to the 2201 Rack Chassis User Manual for diagnostic
procedures for the 2201 Rack Chassis and power supplies.
Required Equipment
1) Multimeter - for AC voltage, resistance and continuity tests
2) Fiber Optic Power Meter - should be calibrated at the correct optical wave length (1300 nm)
withthe appropriate optical connectors
3) A short (one meter or less) 62.5
µ
M fiber optic jumper cable, terminated with the appropriate
connectors
4) A Bit Error Rate Tester (BERT) with the appropriate electrical interface and cable
Step Symptom Possible Cause(s) Action
1 No power indicator No AC power Check AC power source
on front panel(s);
2 No power indicator Defective modem Replace Modem
on front panel(s);
NOTE: Once any power system problems have been corrected, continue the
system checkout after the System Test Diagnostic Procedure.
6.2 System Test Diagnostic Procedure
Step Symptom Possible Cause(s) Action
1 No data transmission Defective fiber optic Set the System Loopback
between modems modem(s), cable(s) switch on one modem. Verify
or connectors the proper operation of the test
(refer to Chapter 5). If the test
is successful, proceed to Step
5. If the test fails, continue to
the next step.
2 Verify the optical cable loss. Remove the Tx fiber from the modem. Use the optical
power meter and fiber optic jumper cable to determine the optical launch power for this
modem. Reconnect the Tx fiber to the modem. Remove the Rx fiber from the modem
and determine the optical receive power into this modem. Reconnect the Rx fiber to the
modem. Repeat these steps for the modem at the other end and record both optical
power levels.
NOTE: Optical power readings are dependent on data rate. To make accurate optical
power measurements, use a 20 Mbps data rate. If the modem is normally operating at a
rate other than 20 Mbps, use the internal clock mode to obtain the maximum operating
speed (refer to Section 2.7.2). The standard Internal Clock Oscillator (-08) with a rate
switch setting of CCC results in an operating speed of 20 Mbps. Use this mode and speed
for making optical power measurements.