2801 Router /w PVDM2-8 use both G711 & G729?

[mattsmith]

I have a 2801 Router /w PVDM-8 and 4port FXO card.

When a call comes in from the PSTN and the phone is not answered it is transfer to Unity in a different region.

0/2/2         g711ulaw   n  S_CONNECT             FXOLS_CONNECT

If I change the codec to g729 between regions in CUCM7.1 the transfer fails.

When I change the codec between regions back to g711 the transfer works.

I have 3 other Routers 2811,2821,1760 in different regions.

When a call rings a phone the codec starts out as a G711 but when the transfer to Unity begins the codec on the Router changes to g729.

The codec between CUCM regions is G729.

Note: There are no transcoders configured in CUCM.

Is there a difference in the 2801 Router compared to the others?

What is my next step to resolve the issue above and use only G729 on the WAN.

Thanks

Matt

[Brandon Buffin · Accepted solution]

Matt,

     Is the gateway using MGCP or H.323? If H.323, did you change the dial peer to reflect the codec change?

Brandon

[mattsmith]

MGCP.

I should have said that all the Gateways are MGCP controlled.

Thanks

Matt

[Brandon Buffin]

If you change the CFNA destination to a phone in the same region as Unity (as opposed to sending the call to Unity), does the call succeed?

Brandon

[mattsmith]

It does when the bandwidth is set to G711 between sites

It fails when the bandwidth is set to G729 between sites

I do not see the gateway ever move to G729... on the 2801 Router.

sh voice call summary

Thanks

Matt

[ssadayap]

Could you please check the default codec configuration in unity side. AFIK the default codec will g711 in unity.  http://www1.cisco.com/en/US/docs/voice_ip_comm/unity/white/paper/cuaudiocodecs.html#wp64723

  You can find the list of supported codec in the above link

[Brandon Buffin]

Matt,

     CFNA to Unity is working from other sites using g.729 right? Be default, Unity can transcode on the fly in software.

Brandon

[Steven Holl]

When exactly is it g711?  When the call is answered by Unity?  Perhaps Unity is only accepting g711 calls, because the prompts are g711?

If you can get detailed CM traces and 'debug mgcp pack' you can see what codecs are being send down each leg, and it will shed more light on this.  Something in the path doesn't support g729, it sounds like.  If everything is MGCP, you have no dial-peers to worry about there.  In CM, IP phones will support g729 in the g711 region, so my hunch is that Unity isn't configured for g.729 calls, in which case you'd need a transcoder at CM or Unity installed to support g729.