Cisco 7975G - Page 180

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Cisco Unified IP Phone 7975G Administration Guide for Cisco Unified Communications Manager 6.0
OL-12642-01
Chapter 9 Troubleshooting and Maintenance
General Troubleshooting Tips
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.
The 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 7-13
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 are being used in 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 7-13
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 7-13
for information about displaying these statistics.
Loopback condition A loopback condition can occur when the following
conditions are met:
• The SW Port Configuration option in the
Network Configuration menu on the phone is set
to 10 Half
(10-BaseT/half duplex)
• The phone receives power from an external
power supply
• The phone is powered down (the power supply
is disconnected)
In this case, the switch port on the phone can become
disabled and the following message will appear in
the switch console log:
HALF_DUX_COLLISION_EXCEED_THRESHO
LD
To resolve this problem, re-enable the port from the
switch.
Table 9-2 Cisco Unified IP Phone Troubleshooting (continued)
Summary Explanation