Just installed a sl1100 with sip trunks. I am experiencing phantom ringing with the caller ID of 100 or 1001. Happening as much is three times in a row two or three times in an hour. Sip trunks are set up as registration trunks. Please help cannot figure out how to stop it from happening. Everything else is working fine incoming and outgoing calls

Uh oh. The last time it happened to me, it was a port forwarding issue. My Off-premise extension was talking to the World instead of only the PBX. Once I took 5060 out of the router's port forwarding, it stopped.

Carl

Someone is trying to hack the system by trying to find a spare station and call out.. If port 5070 is active in your router remove it. Port 5060 is used for SIP trunking.. Also remove any spare stations from the port and virtual numbering scheme..