We have CUCM (v 7.1.5) connected to a SIP provider using a SIP trunk.
The sip provider only accepts G729, so I created a new Region and Device Pool to use G729 as the audio codec and assigned the SIP trunck to it.
Also I am using MTP in the SIP trunk configuration, and I have MRG defined that contains MTP's
My probelm is that when I place the call from my IP Phone 7940, there is no SDP sent to the provider so no negotiation occurs and the call drops.
So can any one help me how can I place calls using G729 codec over a SIP trunk
First of all CUCM based MTP is only G711 you will need to define IOS MTPs as G729, you can define software IOS MTPs wuthout the need for PVDMs. Also, I would strongly suggest you use a CUBE for your deployment as that supports Early-Offer natively.