Cisco 3951 Administration Manual page 96

General Troubleshooting Tips for the Cisco Unified IP Phone
Table 7-1 Cisco Unified IP Phone Troubleshooting (continued)
Summary
Codec mismatch between the phone
and another device.
Sound sample mismatch between the
phone and another device.
Gaps in voice calls.
Checking signaling.
Checking the handset cradle clip.
Cisco Unified SIP Phone 3951 Administration Guide for Cisco Unified CallManager 5.1
7-14
Explanation
The RxType and the TxType that is being used for a
conversation between this IP phone and the other device 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.
The size of the voice packets that are being used in a
conversation between this IP phone and the other device should
match.
Can be caused by a problem with jitter on the network or
periodic high rates of network activity.
To check that signaling is working properly between the phone
and Cisco Unified CallManager, press the Speaker button on
the phone to answer a call. If you can answer a call and if you
hear a dial tone, signaling is working properly.
Cisco Unified IP Phones are designed with a reversible handset
clip in the cradle. This clip is used with the plastic tab
protruding out when the phone is in a vertical (wall-mounted)
position. The position of the tab can interfere with the handset
as it is placed in the cradle. If the phone remains in the on-hook
position you may experience continued ringing when you try to
answer a call or a lack of dial tone when you try to place a call.
To resolve this problem, you may need to reverse the clip.
If the handset cradle clip is in the wall-mounted position and
your phone is placed on a desktop, slide the clip upward to
remove it. Rotate the clip 180 degrees and slide it back in so that
the tab is hidden.
If the hook switch remains in the down position, tapping on the
phone should free up the switch. You can also try pushing and
suddenly releasing the off-hook button after the handset has
been picked up.
Chapter 7 Troubleshooting and Maintenance
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