Specifications

9-15
Cisco Unified Wireless IP Phone 7921G Administration Guide for Cisco Unified CallManager Release 4.1, 4.2, 5.0
OL-10802-02
Chapter 9 Troubleshooting the Cisco Unified Wireless IP Phone 7921G
Resolving Voice Quality and Roaming Problems
Note With DTCP, if Client Transmit Power is set in the access point, the phone
automatically uses the same client power setting. If the access point is set
for the maximum setting (Max), the access point uses the Transmit Power
setting on the phone.
• Check that the access point is enabled for ARP caching. When the
Cisco
Unified Wireless IP Phone 7921G is in power save mode or scanning,
the access point can respond to the wireless IP phone only when ARP caching
is enabled.
See the “Voice Over IP Wireless Network Configuration” section on
page 2-27 for more information.
• Check your gateway and IP routing for voice problems.
• Check if a firewall or NAT is in the path of the RTP packets. If so, you can
use Cisco IOS and PIXNAT to modify the connections so that two-way audio
is possible.
• Check that the Data Rate setting for the phone and the access point are the
same. These settings should match or the phone should be set for Auto.
• Check the phone hardware to be sure the speaker is functioning properly.
• Check the volume settings in the Phone Settings menu.
Symptom: The unified IP phone Does Not Roam Properly
If users report that when engaged in an active phone call and walking from one
location to another (roaming), the voice quality deteriorates or the connection is
lost, you can use the following suggestions to identify the cause of the problem.
These sections can assist you with the following symptoms:
• Voice Quality Deteriorates While Roaming, page 9-16
• Delays in Voice Conversation While Roaming, page 9-16
• Phone Loses Connection with Cisco Unified CallManager While Roaming,
page 9-16