How to factory reset Cisco 7800 series phone

Step 1 Unplug the phone:
If using PoE, unplug the LAN cable.
If using the power cube, unplug the power cube.

Step 2 Wait 5 seconds.

Step 3 Press and hold # and plug the phone back in.

Step 4 When the light on the Mute button and handset light strip turns off and all other lights (Line button, Headset button, Speakerphone button, and Select button) stay green, press 123456789*0# in sequence.

When you press 1, the lights on the line buttons turn red. The light on the Select button flashes when a button is pressed.

After you press these buttons, the phone goes through the factory reset process.
If you press the buttons out of sequence, the phone powers on normally