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Monitoring and Testing
4-14
3166-A2-GB20-10
November 1998
Troubleshooting
The DSU/CSU is designed to provide you with trouble-free service. However,
Table 4-6 gives you some direction if a problem occurs.
For problems other than those listed in the table, please contact your service
representative.
Table 4-6. Troubleshooting (1 of 2)
Symptom
Possible Cause Solutions
No power 1. The power module is not
securely attached.
2. The wall receptacle has no
power.
1. Check the power module
attachment.
2. Check the wall receptacle
power by plugging in some
equipment that is known to be
working.
Power-Up
Self-Test fails
The DSU/CSU has detected an
internal hardware failure.
Contact your service
representative.
Message LOS at
NET appears
1. Network cable problem.
2. No signal is being transmitted
at the far-end.
3. Facility problem.
1. Check that the network cable
is securely attached at both
ends.
2. Check the far-end status.
3. Contact your facility provider.
Message OOF at
Net appears
1. Incompatible framing format
between the network and the
DSU/CSU.
2. Network cabling problem.
3. Facility problem.
1. Check that the framing format
for the network interface is
correct.
2. Check that the network cable
is securely attached at both
ends.
3. Contact your facility provider.
Message
Yellow at Net
appears
1. Network cable problem.
2. Far-end device has lost
framing sync on the line.
3. Facility problem.
1. Check that your network
cable is securely attached at
both ends.
2. Check the status of the
far-end device.
3. Contact your facility provider.
Message
AIS at Net
appears
1. Upstream device is
transmitting an AIS.
2. The network is transmitting
an AIS.
1. Check the status of the
upstream device(s).
2. Contact your facility provider.
Message EER at
Net appears
Facility problem. Contact your facility provider.