Step 1
Remove power from the phone in one of these ways:
Unplug the power adapter.
Unplug the LAN cable.
Step 2
Wait 5 seconds.
Step 3
Press and hold # and plug the phone back in.
Step 4
When the Headset and Speaker buttons are lit, release # and enter the following key sequence:
123456789*0#
The light for the Headset button turns off after you press the 1 key. After you enter the key sequence, the Mute button lights up.
Caution: Do not power down the phone until it completes the factory reset process and the main screen appears.
The phone then resets.