Specifications

2-5
Cisco ONS 15454 Troubleshooting and Maintenance Guide
November 2001
Chapter 2 General Troubleshooting
Step 1 Test the test set with a hard loop.
To perform a hard loop, bridge the test set transmit (Tx) and receive (Rx) terminals with a cable and send
traffic across this loop to ensure that the test set works.
Step 2 Use appropriate cabling to attach the electrical test set transmit (Tx) and receive (Rx) terminals of the
test set to the EIA connectors or DSx panel for the port you are testing. Both transmit (Tx) and receive
(Rx) connect to the same port. Set up the test set accordingly.
Step 3 In node view, double-click the card where you will perform the loopback.
Step 4 Click the Maintenance > Loopback tabs.
Step 5 On the Loopback subtab, select Facility (Line) from the Loopback Type column for the port being
tested. If this is a multiport card, such as the OC3, make sure to select the appropriate row for the desired
port.
Step 6 Click Apply.
Step 7 On the confirmation dialog box, click Ye s.
Note It is normal for an alarm to appear during loopback setup. The alarm clears when you remove
the loopback.
Step 8 If the test set is not already sending traffic, send test set traffic on the loopback circuit.
Step 9 Examine the traffic received by the test set. Look for errors or any other signal information that the test
set is capable of indicating.
Step 10 If the test set indicates a good circuit:
a. Clear the Facility Loopback:
On the Loopback subtab, select None from the Loopback Type column.
Click Apply.
b. Skip to the “Perform a Hairpin on a Source Node” procedure on page 2-8.
Step 11 A faulty circuit signifies a problem with the DS-N card, the cabling from the DS-N card to the DSx panel,
or the EIA. Test the DS-N cabling, the DS-N card, and then the EIA.
Step 12 To test the cabling:
a. Replace the suspect cabling (the cables from the test set to the EIA ports) with a known good cable.
b. If a known good cable is not available, test the suspect cable with a test set. Remove the suspect
cable from the EIA and connect the cable to the transmit (Tx) and receive (Rx) terminals of the test
set. Run traffic to determine whether the cable is good or suspect.
c. Resend test set traffic on the loopback circuit with a known good cable installed.
d. If the circuit is now good, the problem was probably the defective cable. Replace this cable and skip
to the “Perform a Terminal Loopback on a Destination DS-N Card” procedure on page 2-6.
Step 13 To test the card:
a. Replace the suspect card with a known good card.
b. Resend test set traffic on the loopback circuit with a known good card.
c. If the circuit is now good, the problem was probably the defective card. Replace the suspect card
and skip to the “Perform a Terminal Loopback on a Destination DS-N Card” procedure on page 2-6.