Occasionally you may need to restart or power-cycle a Cisco desk phone to get it operational again. This is very easy to do.
\uD83D\uDCD8 Instructions
Turn the phone over and look for the two RJ-45 network jacks on the left side of the phone.
If there are two jacks, one connects to the NAM and the other provides pass-through network connectivity to your computer.
Disconnect the jack on the left, the one with the ethernet symbol above it:
. Leave the cable disconnected for 5 seconds. This is port 2 in the image below:
Plug the cable back in and you’ll see the Cisco logo on the display, indicating the phone is restartarting.
See the video below for a walk-through of this process