14-57
Cisco ONS 15327 User Documentation, R3.3
June 2002
Chapter 14 Alarm Troubleshooting
Alarm Procedures
Step 6
Repeat Steps 1 to 5 for another port on the card.
Step 7
Look for another alarm that may identify the source of the problem.
Step 8
Replace the reporting card.
Note
When you replace a card with an identical type of card, you do not need to make any changes to
the database.
14.4.77 LOS (OC-N)
•
Critical, Service-Affecting
A port on the reporting OC-N card has a loss of signal (LOS) condition. An LOS occurs when a SONET
receiver detects an all-zero pattern for 10 microseconds or longer. An LOS means the upstream
transmitter has failed. If an OC-N LOS alarm is not accompanied by additional alarms, a fiber break is
usually the cause of the alarm. The condition clears when two consecutive valid frames are received.
Warning
Invisible laser radiation may be emitted from the aperture ports of the single-mode, fiber-optic
modules when no cable is connected. Avoid exposure and do not stare into open apertures.
Caution
Always use the supplied ESD wristband when working with a powered ONS 15327. Plug the wristband
cable into the ESD jack located on the lower-right outside edge of the shelf assembly.
Procedure: Clear the LOS Alarm on an OC-N Card
Step 1
Verify fiber continuity to the port.
Step 2
Verify that the correct port is in service.
Step 3
Use an optical test set to verify that a valid signal exists on the line.
Test the line as close to the receiving card as possible.
Step 4
Clean the fiber:
a.
Clean fiber according to local site practice.
b.
If no local practice exists, use a CLETOP Real-Type or equivalent fiber-optic cleaner and follow the
instructions accompanying the product.
Step 5
Verify that the power level of the optical signal is within the OC-N card receiver specifications.
Step 6
If there is a valid signal, replace the connector on the backplane.
Step 7
Repeat Steps 1 to 5 for another port on the card.
Step 8
Replace the OC-N card.
Summary of Contents for ONS 15327
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Page 30: ...Figures xxviii Cisco ONS 15327 User Documentation June 2002 ...
Page 44: ...Procedures xlii Cisco ONS 15454 Installation and Operations Guide R3 2 June 2002 ...
Page 540: ...Glossary GL 16 Cisco ONS 15327 User Documentation R3 3 June 2002 ...