Codec Question

[linuxchild]

I have configured a back to back BRI interface on 2821 router using ISDN

I set 2 phones under my CME

phone A : G729 codec

phone B : G729 codec

I made a call by using BRI port

phone A >> BRI1>>>BRI2>>phone B

when I do sh voice call summary , I get

PORT           CODEC     VAD VTSP STATE            VPM STATE

============== ========= === ==================== ======================

0/0/0.1       g729r8     n  S_CONNECT             S_TSP_CONNECT

0/0/0.2       -          -  -

0/0/1.1       g729r8     n  S_CONNECT             S_TSP_CONNECT

...

...

...

50/0/1  .1       g729r8     n  S_CONNECT             EFXS_CONNECT

50/0/1  .2       -          -  -                     EFXS_ONHOOK

50/0/2  .1       g729r8     n  S_CONNECT             EFXS_CONNECT

below is dsp-group aoutput

dsp 1:

  State: UP, firmware: 28.3.1

  Max signal/voice channel: 16/16

  Max credits: 240

  num_of_sig_chnls_allocated: 16

  Transcoding channels allocated: 0

  Group: FLEX_GROUP_VOICE, complexity: FLEX

    Shared credits: 180, reserved credits: 0

    Signaling channels allocated: 16

    Voice channels allocated: 2

    Credits used (rounded-up): 60

    Voice channels:

      Ch01: voice port: 0/0/1.1, codec: g729r8, credits allocated: 30

      Ch02: voice port: 0/0/0.1, codec: g729r8, credits allocated: 30

normally isdn use G711 , so there must be a transcoding  ?? does this mean that the router converted the outgoing call to G711 then converted the incoming call from G711 to G729 ?? or just transport the flow from end to end using G729 ?

thank you in advance for clarifying this point

Rgards

[phooghen]

The 2 phones will talk together using G.729. The router will convert the VOIP G.729 to G.711 and send it to BRI and the G.711 from BRI to VOIP G.729 by using the BRI DSP.

Therefore there is no need to add extra DSP for transcoding.

Pierre.

[linuxchild]

thank you

but what debug command allow me to see this process ?? I mean the conversion process ??

I tried to remove all the pvdm from my router , but my call did not work , I did not even get voice port in my running config

me too , I thought that BRI has integrated dsp ?? strange ?

back  back to the original question how can I see the process of conversion knowing that I have this output

PORT           CODEC     VAD VTSP STATE            VPM STATE

============== ========= === ==================== ======================

0/0/0.1       g729r8     n  S_CONNECT             S_TSP_CONNECT

0/0/0.2       -          -  -

0/0/1.1       g729r8     n  S_CONNECT             S_TSP_CONNECT

0/0/0.1 is the BRI port 0

and

0/0/1.1 is the BRI port 1

and from the DSP out put command  , this is confirmed

Ch01: voice port: 0/0/1.1, codec: g729r8, credits allocated: 30

Ch02: voice port: 0/0/0.1, codec: g729r8, credits allocated: 30

Regards