I moved customer's NEC Aspire IP1NA system to new location.
There was no power in IT room so I plugged in KSU in another room and waited for electrician to get power to IT room.
Now 60% of the time when I plug in or unplug a phone seems phone displays go blank entirely.
I reboot and it comes up after few minutes.
Any thoughts to a fix?

Thank you


Telesystems technician