IP Phone Registration

[Naisamuddin pk]

Dear Team,

              I am having 116 number of  7911 series IP Phone and Call Manager version 7.1. The IP Phones are installed at one of the branch site. The IP phone some time getting unregistered with call manager. If am restarting the IP phone, it is again working fine but after 15 or 20 minutes it is again unregistering. In call manager it is showing the error DirectoryNumberMismatch.  Please give me one solution to  trouble shoot this issue.

Many Thanks,

Naisamuddin Pk

[Joseph Martini]

In the application logs (Event Viewer - Application Logs) from the real time monitoring tool, find the device name of the phone that unregistered and then look for the reason code value and use this document to decode it: http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/err_msgs/7_x/ccmalarms712.html.  The most common is reason code 13, keep alive timeout meaning traffic isn't getting back and forth between the phone and call manager.