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Monitoring and Testing
4-93163-A2-GB20-10 March 1999
Table 4-4
(2 of 2)
Troubleshooting
Symptom SolutionsPossible Cause
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.
A failure message
appears followed
by an 8-digit code
(
x
x
x
x
x
x
x
x
)
Internal DSU/CSU problem. Record the 8-digit code, then contact your
service representative.
Mgmt link is down 1. The manager configuration is mismatched with
the DSU/CSU configuration.
2. The manager’s link layer protocol is not
running.
1. Check that the configurations are matched.
2. Start the link layer protocol.
Invalid Number The modem cannot dial because the phone
number is invalid or there is no number in the
selected directory.
Check that the selected phone number is correct.
No Dial Tone The modem cannot dial because there is no dial
tone.
Check that the modem is connected properly.
Busy Signal The modem is receiving a busy signal. Redial the phone number later.
No Answer Tone The remote end does not answer within
45 seconds.
Redial the phone number later.
Modem In Use The modem is in use. Redial the phone number later.