It looks like the SDP information was being dropped due to G729 being set in the region configuration.
This has been changed to G711 and MTP is enabled on the SIP trunk.
SDP is now being sent but there is no codec specified?
See debug output below on a outbound to PSTN call:
Aug 29 10:50:40.775: //-1/xxxxxxxxxxxx/SIP/Msg/ccsipDisplayMsg:
Received:
INVITE sip:PSTN_NUMBER@CUBE:5060 SIP/2.0
Date: Fri, 29 Aug 2008 10:50:40 GMT
Allow: INVITE, OPTIONS, INFO, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY, PUBLISH
From: <8599>;tag=ec6acf8b-8e42-492f-aa9a-7046172ba6ff-47851882
Allow-Events: presence, kpml
Supported: timer,replaces
Min-SE: 1800
Remote-Party-ID: <8599>;party=calling;screen=yes;privacy=off
Content-Length: 216
User-Agent: Cisco-CUCM6.1
To:
Contact: <8599>
Expires: 180
Content-Type: application/sdp
Call-ID: 50b68580-8b71d480-5a-f2911fac@CUCM6
Via: SIP/2.0/TCP CUCM6:5060;branch=z9hG4bK6411c183e2
CSeq: 101 INVITE
Session-Expires: 1800
Max-Forwards: 70
v=0
o=CiscoSystemsCCM-SIP 2000 1 IN IP4 CUCM6
s=SIP Call
c=IN IP4 CUBE
t=0 0
m=audio 16630 RTP/AVP 0 101
a=rtpmap:0 PCMU/8000
a=ptime:20
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
Aug 29 10:50:40.779: //-1/xxxxxxxxxxxx/SIP/Msg/ccsipDisplayMsg:
Sent:
SIP/2.0 488 Not Acceptable Media
Via: SIP/2.0/TCP CUCM6:5060;branch=z9hG4bK6411c183e2
From: <8599>;tag=ec6acf8b-8e42-492f-aa9a-7046172ba6ff-47851882
To: ;tag=DD1C0BAC-DC1
Date: Fri, 29 Aug 2008 10:50:40 GMT
Call-ID: 50b68580-8b71d480-5a-f2911fac@CUCM6
Server: Cisco-SIPGateway/IOS-12.x
CSeq: 101 INVITE
Allow-Events: telephone-event
Reason: Q.850;cause=65
Content-Length: 0
