After going through a number of scenarios (including using a Handytone 486 ATA, and running a Trixbox setup), I'm trying to get the phone back to the bare basics to make it stable before I end up in divorce court!

Summary:
- Running a single Cisco 7912 flashed to SIP and configured for Xnet
- Router (DSE XH9949) has NAT's for TCP/UDP 5060 and TCP/UDP 10000-11000 through to the IP of the 7912.
- All the switches, wireless, routers, phones etc. have been reset.
- Phone IP is now in the DMZ on the router.

Outgoing calls are OK, but incoming calls go straight to voicemail.

Any tips?

Rich.