I have recently completed an multi-location install encompassing 5 locations with 5 separate UC devices. Each location has a UC500, a separate AIR-AP521, a 7925 IP Phone, and an assortment of other 79XX series IP Phones. At each location, I am having the problem described below with every 7925. All of the other wired IP phones work flawlessly.
The 7925 phone registers to the system and works fine without issues. Without warning, the 7925 will stop passing two-way audio. The callers can hear the person using the 7925, but the person on the 7925 is unable to hear anything on their end.
The problem can be recitified simply by pulling and re-inserting the battery. The phone will boot up and will work without issue for an undetermined amount of time. Sometimes days, sometimes just a matter of hours. Pulling and re-inserting the battery always fixes it.
The wireless configuration is pretty standard. We have separate SSIDs/VLANs for data and voice. We're using WPA-PSK to secure the WLANs.
The 7925 is always within 50 feet of the access point. These access points only service 1 7925 and normally service no data clients except for the occasional laptop they may be brought in.
All of the UCs are running the 7.1.1ea software pack. The 7925s using the phone loads included with the 7.1.1ea software pack.
I don't believe this to be a configuration problem, and I'm leaning more towards a firmware problem. I wasn't able to find anything in the Cisco bug tracking system. I thought I would ask the Cisco community at large to see if anyone else has had similar problems.