[asterisk-users] ConfBridge dtmf_passthrough=no doesn't have any effect. Bug?

Markus universe at truemetal.org
Fri Sep 28 08:39:41 CDT 2012


Hi again Leif,

Am 28.09.2012 13:42, schrieb Leif Madsen:
>> OH! I just tested with a SIP softphone (X-Lite), and DTMF does not get
>> passed to the other users! In X-Lite I can hear the DTMF keypresses of
>> the users connected via PSTN (incoming via SIP), but when I hit a key in
>> X-Lite I can't hear that on the PSTN phones. Hmmm ...
>
> I am not referring to your previous posts, but your test and results
> seem to indicate what I had somewhat thought.
>
> When you're using X-Lite, you're likely using RFC2833 for the DTMF
> method, which is out of band, and gets absorbed by Asterisk by it not
> playing the DTMF into the conference. This is how it should work (and
> likely does for most scenarios/phones).
>
> It sounds like maybe either a configuration or implementation issue on
> the carrier side though. Are you using inband DTMF there? Asterisk
> should really be absorbing that too, but sometimes it can't get it all.
> If you switch to an out of band method like info or rfc2833, does that
> help?
>
> Do you hear the DTMF on a normal call outside of ConfBridge() with the
> same carrier?
>
> I suspect this isn't a ConfBridge() problem, but a general DTMF one.
> Nice idea on the dtmf_passthrough setting, but it's not really the
> solution to your problem here.

Thanks for the suggestions. (RFC2833 was already set on the SIP peer in 
question)   For further debugging I've just done the following tests 
with these results:

DID provider 1, incoming via SIP (Germany):

PSTN to DID to X-Lite, RFC2833: hear DTMF, not logged on console
PSTN to DID to X-Lite, inband: hear DTMF, not logged on console
PSTN to DID to X-Lite, INFO: hear DTMF, not logged on console

PSTN to DID to ConfBridge, RFC2833: hear DTMF, LOGGED on console
PSTN to DID to ConfBridge, inband: hear DTMF, not logged on console
PSTN to DID to ConfBridge, INFO: hear DTMF, not logged on console


DID provider 2, incoming via SIP (UK and Netherlands):

PSTN to DID to X-Lite, RFC2833: hear DTMF, LOGGED on console
PSTN to DID to X-Lite, inband: hear DTMF, LOGGED on console
PSTN to DID to X-Lite, INFO: hear DTMF, not logged on console

PSTN to DID to ConfBridge, RFC2833: hear DTMF, LOGGED on console
PSTN to DID to ConfBridge, inband: hear DTMF, LOGGED on console
PSTN to DID to ConfBridge, INFO: hear DTMF, not logged on console


DID provider 3, incoming via SIP (Nigeria and Kazakhstan):

PSTN to DID to ConfBridge, inband: hear DTMF, LOGGED on console


DID provider 4, incoming via SIP (US):

PSTN to DID to ConfBridge, RFC2833: hear DTMF, LOGGED on console


X-Lite 3.0 to ConfBridge:

X-Lite peer is set to dtmfmode=rfc2833 in Asterisk.

X-Lite force inband YES, RTP 2833 YES: don't hear DTMF, LOGGED on console
X-Lite force inband NO, RTP 2833 YES: don't hear DTMF, LOGGED on console
X-Lite force inband YES, RTP 2833 NO: hear DTMF, not logged on console
X-Lite force inband NO, RTP 2833 NO: don't hear DTMF, LOGGED on console

The last result is kinda strange. Hm.


PSTN means that I've tested two times, from a regular landline and from 
a mobile. Always calling to the providers DID which ends up in Asterisk 
via SIP. In the case of ConfBridge there were always 2 participants in 
the conference so that I could check if I hear the DTMF on the "other end".

"not logged on console" means that I can hear the DTMF tones in 
X-Lite/ConfBridge but Asterisk doesn't seem to recognize them (which is 
fine as not all providers support all DTMF variants).

My resume is: DTMF is just fine, ConfBridge dtmf_passthrough is not 
working at all. Agree? :)


Thank you,
Markus








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