Specifications

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Cisco ONS 15454 Troubleshooting and Maintenance Guide
November 2001
Chapter 1 Alarm Troubleshooting
1.3.109 SQUELCH
• Not Alarmed, Non-service affecting
The Squelch alarm occurs in a BLSR when a a node that originates or terminates STS circuits fails or is
isolated by multiple fiber cuts. The isolation or failure of the node will disable the circuits that originate
or terminate on the failed node. Squelch alarms appear on one or both of the nodes on either side of the
isolated/failed node. The AIS-P alarm will also appear on all nodes in the ring, except the isolated node.
Caution Always use the supplied electrostatic discharge wristband when working with a powered ONS 15454.
Plug the wristband cable into the ESD jack located on the lower-right outside edge of the shelf
assembly.
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.
Warning On the OC-192 card, the laser is on when the card is booted and the safety key is in the on position
(labeled 1). The port does not have to be in service for the laser to be on. The laser is off when the
safety key is off (labeled 0).
Warning Invisible laser radiation may be emitted from the end of the unterminated fiber cable or connector.
Do not stare into the beam directly with optical instruments. Viewing the laser output with certain
optical instruments (for example, eye loupes, magnifiers, and microscopes) within a distance of
100 mm may pose an eye hazard. Use of controls or adjustments or performance of procedures
other than those specified may result in hazardous radiation exposure.
Procedure: Clear the SQUELCH Condition
Step 1 Determine the isolated node:
a. Display the CTC network view.
b. The grayed out node with red spans will be the isolated node.
Step 2 Verify fiber continuity to the ports on the isolated node.
Step 3 Verify that the proper ports are in service.
Step 4 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 5 Verify that the power level of the optical signal is within the optical card’s receiver specifications. Each
individual card section in Chapter 4 lists the receiver specifications for that card.
Step 6 Ensure that the optical transmits and receives are connected properly.
Step 7 Replace the OC-N card.