I can get it to make and receive regular calls, but it seems to ignore intercom calls and pages.
Here is a log snippet from an attempted intercom call.
The phone gets the INVITE, but it does nothing. No ring or indication of any kind.
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] v=0..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] o=root 4659 4659 IN IP4 192.168.0.14..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] s=session..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] c=IN IP4 192.168.0.14..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] b=CT:384..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] t=0 0..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] m=audio 10048 RTP/AVP 0 8 3 101..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] a=rtpmap:0 PCMU/8000..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] a=rtpmap:8 PCMA/8000..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] a=rtpmap:3 GSM/8000..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] a=rtpmap:101 telephone-event/8000..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] a=fmtp:101 0-16..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] a=ptime:20..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] a=sendrecv..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] m=video 10072 RTP/AVP 99..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] a=rtpmap:99 H264/90000..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] a=sendrecv..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Active subscribe dialogs: 1
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Received message:.
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] INVITE sip:[email protected]:5060;intercom=true SIP/2.0..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Via: SIP/2.0/UDP 192.168.0.14:5060;branch=z9hG4bK2c9da19e..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] From: "Phil at Work" <sip:[email protected]>;tag=as36742704..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] To: <sip:[email protected]:5060;intercom=true>..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Contact: <sip:[email protected]>..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Call-ID: <a href="mailto:[email protected]">[email protected]</a>..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] CSeq: 102 INVITE..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] User-Agent: Asterisk PBX..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Max-Forwards: 70..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Date: Thu, 10 Jun 2010 12:27:30 GMT..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Supported: replaces..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Call-Info: <uri>;answer-after=0..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Alert-Info: Ring Answer..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Content-Type: application/sdp..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] Content-Length: 330..
Jun 10 08:27:31 192.168.0.101 GXV3140: [00:0B:82:1F:C3:97][1.0.3.24] ..