UCCX - Agent gets no audio unless they hold/retrieve call

[Clifford McGlamry]

Odd situation that just started happening.  Calls are coming in over a sip trunk, and originally land as G729.  The call is transferred from the phone it lands on via CFA to a UCCX script on another cluster (connected via a SIP trunk).  The call is updated to G711, caller hears hold music during all the transfers.  

Script has no prompts, and is sent to an agent.  

At this point, there is NO AUDIO in either direction.  If the agent puts the call on hold, and then retrieves it, now they can talk to the caller.

I vaguely remember seeing this once before, but I can't remember how to address it.  Anyone else seen this/know how to fix it?

[Elliot Dierksen]

Try setting 'MTP required' on your CTI ports. If you look at your CUBE/SBC, you will probably see the mid-call audio re-negotiating is failing for some reason.

[Clifford McGlamry]

Interesting idea, but that's not really possible.  UCCX CTI ports are SCCP devices.  There is no option for "MTP required" like there is on SIP devices.  

[Elliot Dierksen]

True. You could use the SCCP equivalent of that which would be forcing on 'Use Trusted Relay Point'.