Whenever the 7920 IP phone registers with Cisco CallManager Express through Linksys Access Points, the 7960 IP Phones gets unregistered and is not pingable until the 7920 is powered off and 7960 is replugged to the network

[TCC_2]

Core Issue

If in the middle of a call on the 7960, and a 7920 is powered on, everything is fine. The instant the call on the 7960 is disconnected, the phone un-registers and cannot re-register.

This issue has been seen with Non-Cisco access points (APs).  Technically, Cisco does not support the 7920s with non-Cisco APs because of issues like this.

Resolution

Usage of 7920 IP phones with Linksys Access Points is not supported. As a workaround, you can disable Cisco Discovery Protocol (CDP) on the 7920. In order to disable CDP on the 7920, complete these steps:

1. On the 7920 handset, press - Menu, *, #, #, Send.

      

2. Scroll to Network Config.

      
3. Scroll down until you find CDP TX enable/disable.
   

4. Disable CDP TX.

Refer to Wireless Network and Access Point Configuration section of Setting Up the Cisco Wireless IP Phone 7920  for more information.