Sending DTMF on H323 trunk with G711

Aquarius! · Post by **Aquarius!** » 19 Mar 2010 06:59

Hello,

There is a H323 trunk between an OXE and PSTN.
It is a one way speech connection occures when sending a DTMF signal from PSTN.
Scenario:
OXE site had configured a H323 trunk to be reached PSTN softswitch.
The connectivity is done by G.711 codec. The call is established regarding both directions properly.
If there is a DTMF tone sending from PSTN (it is done by RFC2833 with payload 101 and in H245 as User Input at the same time), only DTMF code could be heared on OXE terminal, the speech is not detected for it (in spite of that it is present in RTP call flow checked by Wireshark). The other direction is working properly, the voice going to PSTN is all right.
In case of G.729 codec there is no problem.
I have cheked scenario in R8 and in R9 as well. It was the same behavior (written above) in both release.
Who knows a similar issue?

Post by **tot3nkopf** » 29 Mar 2010 04:25

In the H.323 traces (t3) what do you see?

Aquarius! · Post by **Aquarius!** » 29 Mar 2010 05:08

Hi,

In t3 trace we can reconize codec type and some Q931 inormations.
The wireshark trace is more detailed. The PSTN softswitch uses both methode (in/outband) to be detected DTMF tone.
If there is only "user input" used (H245) regrding DTMF sending/receiving, there is no problem.
Now the issue is at R&D.

Post by **tot3nkopf** » 29 Mar 2010 06:36

Please give us feedback when received on this.