A few things that can be done while troubleshooting issues with the wireless phones. (the factory reset procedure varies between the phone models, but the rest is applicable across phone types).
1. Factory default the phone by going to Settings - - -> Phone settings - - - > Pressing **2 - - -> Pressing the "yes" softkey.
2. Install the USB driver on a Windows XP PC. Connect the phone via a USB cable and browse to the Web page of the phone by going to https://192.168.1.100 AFTER going to Start - - > Run - - > ncpa.cpl - - > Right click on the “Wireless phone network connection” - - -> Properties - - -> TCP/IP - - - > Use the following IP address - - -> Entered 192.168.1.123 with a mask of 255.255.255.0 - - -> Clicked on OK and then OK again. (The IP address of the computer should be any IP address in the 192.168.1.[1-254] range EXCEPT 192.168.1.100 and any other IP address already being used in the network.)
3. Click on "phone upgrade" and entered admin/Cisco as the username/password. (note that the password has a capital "C")
4. Browse to the TAR file firmware version saved on the computer and upload the firmware on the phone.
5. Once the phone upgrade goes through, modify the Network profile and SSID details to register the phone. Be patient during the phone upgrade - it might take QUITE some time.
6. Add the line buttons through the GUI - only 1 line button seen.
7. Make sure that the IOS/CME and CUE versions are compatible and ensure that the correct GUI file versions have been loaded. This can be checked by going to help - - -> about on the GUI. Reset the phone if the versions are compatible and then check for the line buttons.