Exchange 2007 UM "488 Not Acceptable Here" causes dead air

Unanswered Question

Hello All,

I have a problem with CUCM 7.0.2 with a SIP trunk to Exchange 2007 for unified messaging. The EUM trunk is on direct media "media termination point" is NOT checked. For my setup, I cannot have the MTP. Since it is direct media, when I try to transfer a call (or place the EUM server on hold), the cucm sends a re-invite with the standard hold request sdp line "c=IN IP4". With that, the EUM server responds with a "488 Not Acceptable Here". After that, the call is dead air. The call control on the phone still works as if the call was live, but there is no audio, in or out. The strangest part though is that the EUM server, and the phone are both still sending RTP traffic to each other, but apparently one or both of the endpoints stop processing the RTP data.

On to my actual question... does anyone know of a way (besides enabling "MTP Required") to prevent the CUCM from sending the call hold re-invite (The invite with the addressed sdp)? If I can prevent that part of the CUCM's transfer process, I can hopefully prevent the audio from dying.

Thanks In Advance,


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