G711 to G729 Transcoding

Unanswered Question
Oct 16th, 2008

Can any one give me an example for G.711 to G.729 transcoding? I want to transcode H.323 call from G.711 to G.729 on a C2800 router with PVDM2-64. I don't have either CUBE or CCM.

I found below link states the G.711 to G.729 transcoding on H323 call. But somehow the configuration doesn't seem to be matched that scenario. It uses SCCP instead.



I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4 (2 ratings)
Chris Deren Thu, 10/16/2008 - 09:59

What are you attmepting to do? What are the devices that you are attmepting to transcode between?

The example is correct, the transcoder configuration on the GW is using SCCP to register with CallManager, and then CallManager invokes the transcoder when necessary.

We need more details on your environemnt to assist.


Brandon Buffin Thu, 10/16/2008 - 10:05

The config in the link you posted should work for your scenario. This example in the "Full Sample Configurations for Internal Transcoding" section registers the transcoder with a local instance of CME (as indicated by the "telephony-service" section of the config). This process does use SCCP for registration. You can also register the transcoder with SRST if you happen to be using this.

Hope this helps.


David Lin Thu, 10/16/2008 - 11:49

Thanks Chris, Brandon.

I don't use CCM in this case. The scenario is:

Origination Gateway-(H.323/G.711)->C2800-(H.323/G.729)->Termination Gateway

I may send the call by SIP as well. Both Origination and termination Gateway are 3rd-party product which support H323 and SIP.

I tired 2 images but no luck.



I also refer to another link but it doesn't work.


Brandon Buffin Thu, 10/16/2008 - 11:54

You don't have to use CCM. You can configure CME locally on the router for the purpose of registering the transcoder as in the link or you can use SRST.


David Lin Thu, 10/16/2008 - 12:20


So IP to IP gateway feature can't run independently? I have to install CME on 2800 and make transcoder to be associated as below?

dspfarm profile 1 transcode

codec g711ulaw


associate application SCCP <<<---

I just find my image supports CME3.0. I thought I have to buy the license:)

David Lin Thu, 10/16/2008 - 13:29

How can I verify this feature is functioning?

I configured the router same as that link. But I can't find the transcode is registered.

Router#sh sdspfarm units

mtp-1 Device:XCODE123456 TCP socket:[-1] UNREGISTERED

actual_stream:0 max_stream 0 IP: 0 Unknown 0 keepalive 0

max-mtps:1, max-streams:20, alloc-streams:0, act-streams:0


This Discussion