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New Member

Codec selection between CME/CUE and UCUM

I have question that  I'm hoping to gain a better insight/clarification to the Codec selection process on h323 dialpeers and CUCM regions.

Scenario: An h323 trunk between a CUCM cluster and a CME/CUE ISR. Typical scenario of utilizing g729 over the WAN, but of course CUE can only use g711. Currently, a transcoder on the CME is allowing this to work properly.

Question: Is there any way to configure this in such a way that when two IP phones connect, g729 is established, but if the CME phone forwards the call  to the CUE Pilot, the CUCM Phone will establish g711 to the CUE eliminating the need for a transcoder?

Comments/Questions are appreciated!

Everyone's tags (3)
VIP Super Bronze

Re: Codec selection between CME/CUE and UCUM

Yes, use the a voice class codec command. VoIP dial peers use g729 by default. A voice class allows you to specify an list of multiple codecs that will be included in the H.245 capabilities exchange. The order of the codecs listed indicates their preference.

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New Member

Re: Codec selection between CME/CUE and UCUM

Thanks for the reply Jonathan, I am familiar with voice class codecs, but still wondering if it's possible to utilize 729 for CUCM <-> CME phone-to-phone calls, while renegotiating to 711 when transferred by the CME phone to the CUE.

I am going to experiment by labbing it - but just looking for any insight others may be able to offer.