codec pass-through

[j.a.m.e.s]

Dear All,

Could anyone explain what codec pass-through does under dspfarm please? It is available under the transcoder and mtp resources:

dspfarm profile 4 transcode universal
 description XCODE
 codec g711alaw
 codec g711ulaw
 codec g729r8
 codec g722-64
 codec pass-through
 maximum sessions 4
dspfarm profile 1 mtp
 description SWMTP G729
 codec g729r8
 codec pass-through
 maximum sessions software 50
 associate application SCCP
dspfarm profile 2 mtp
 description SWMTP ALAW
 codec g711alaw
 codec pass-through
 maximum sessions software 50
 associate application SCCP
dspfarm profile 3 mtp
 description SWMTP ULAW
 codec g711ulaw
 codec pass-through
 maximum sessions software 50
 associate application SCCP

I ask this in the context of my ITSP only supporting rfc2833 and thanks to Jonathan's excellent post, I know that CTIQBE/UCCX only supports KPML/OOB:

https://community.cisco.com/t5/contact-center/dtmf-not-working-with-uccx/td-p/2317592

I can see some strange messages in the CallManager traces relating to CUBE -> UCCX calls:

MrmAllocateMtpResourceReq: If pt cap is requested , try to allocate rtcp pt capable mtp

My assumption is that codec pass-through means the DSPs will handle RTCP, but how this is relevant to UCCX and rfc2833 I don't know?

Regards

James.

[Nithin Eluvathingal]

Have a look on below thread.

https://community.cisco.com/t5/ip-telephony-and-phones/question-on-codec-pass-through/td-p/2775363

[j.a.m.e.s]

Thank you Nithin, that's exactly what I was looking for!

As a follow-on question, do you know if there are any negative effects of adding codec pass-through under the transcoder? What I mean is, will the transcoder still be able to do g711-g729 conversion, but adding pass-though will allow additional beneifts like dtmf interop?

Regards

James.