Audio quality between VCS and CUCM

[gerbenhwk]

Hi,

We have configured a SIP trunk between our VCS and CUCM 8.6. When a telepresence call comes in on our VCS we can route it to a Cisco 9951 IP Phone. When the call has been setup, we have good video and audio.

But the audio is G711 and I would like to have a better audio quality, which I have when the call is answered on an E20 (registered to the VCS)

Does anyone know if we can use an other wideband/HD audio codec in this configuration?

thanks

[admin11111]

On VCS we pass the SDP transparently for the most part, there are little tweaks that happen with the advanced zone configs, but that's to help interop not to force codec selection.

CUCM has the ability to prefer codec selection though, it's usually used to select a low bandwidth codec for running over the WAN.

A 9951 and E20 should be able to do g.722.

Can you perform a trace line side on the 9951 and see if the SDP looks the same by the time it hits the VCS?

Also raising a case with TAC may also prompt a quicker answer than this forum.

Thanks

Richard