Earwig

We have 6416D+ phones and one user is having problem where the phone basically goes dead. The lights turn off and the display goes blank for a brief time and then goes back on. This has also happend when the person was on the phone and the call got disconnected.

I have changed phones and the phone line from the jack to the phone. I was curious what you all would do next? Could it be the port on the network switch that it is plugged through, the phone port that is on the switch?

Any troubleshooting ideas would be greatly appreciated.

Eric