Chapter9 Troubleshooting and Maintenance
General Troubleshooting Tips
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Cisco Unified IP Phone Administration Guide for Cisco Unified CallManager 5.1 (SIP), Cisco Unified IP Phones
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Changing the telephone
configuration
By default, the network configuration options are locked to
prevent users from making changes that could impact their
network connectivity. You must unlock the network
configuration options before you can configure them. See the
“Unlocking and Locking Options” section on page4-4 for
details.
LCD display issues. If the display appears to have rolling lines or a wavy pattern, it
might be interacting with certain types of older fluorescent
lights in the building. Moving the phone away from the lights,
or replacing the lights, should resolve the problem.
Dual-Tone Multi-Frequency
(DTMF) delay
When you are on a call that requires keypad input, if you press
the keys too quickly, some of them might not be recognized.
Codec mismatch between the phone
and another device
The RxType and the TxType statistics show the codec that is
being used for a conversation between this Cisco
Unified IP phone and the other device. These values of these
statistics should match. If they do not, verify that the other
device can handle the codec conversation or that a transcoder is
in place to handle the service.
See the “Call Statistics Screen” section on page 7-16 for
information about displaying these statistics.
Sound sample mismatch between the
phone and another device
The RxSize and the TxSize statistics show the size of the voice
packets that is being used a conversation between this Cisco
Unified IP phone and the other device. The values of these
statistics should match.
See the “Call Statistics Screen” section on page 7-16 for
information about displaying these statistics.
Gaps in voice calls Check the AvgJtr and the MaxJtr statistics. A large variance
between these statistics might indicate a problem with jitter on
the network or periodic high rates of network activity.
See the “Call Statistics Screen” section on page 7-16 for
information about displaying these statistics.
Table9-2 Cisco Unified IP Phone Troubleshooting (continued)
Summary Explanation