[Asterisk-Users] Polycom IP600 Phantom Ringing

[Ben Ruset]

Hello list:

I have a very odd problem. Seemingly randomly, my Polycom IP600 phones 
will ring without a call being placed to it.

That is to say, a random phone will ring. Nothing shows up under Caller 
ID. Even the buttons that light up to show an incoming call do not light 
up. If you pick up the handset, you can hear the phone ring through the 
speaker.

Hanging up the phone makes it stop ringing. Then, sometime later, it 
will happen on another random extension.

Is this a common problem? Where can I look to start diagnosing this?

Thanks!
-ben