[asterisk-users] DTMF signalling, SIP, and Background()

[Anselm Martin Hoffmeister]

Am Mittwoch, den 26.09.2007, 11:08 +0200 schrieb Bastian Friedrich:
> Hi,
> 
> I am currently setting up a voice mail/IVR machine with asterisk (1.4.10 
> at the moment). During testing and evaluation, all was fine; in the - 
> slightly different - production environment, the IVR contexts do not 
> react sensibly.
> 
> The environment is:
> POTS <-- (ISDN) --> PBX <-- (SIP) --> Asterisk
> with the Asterisk registering with our local PBX.
> 
> When a user reaches the Asterisk machine via this path, key presses are 
> ignored during the Background() function.
> 
> My debugging possibilities have been a little restricted, unfortunately 
> (I'm working on that), but as a wild guess, I suppose we might have the 
> following problem: When a call is processed as a SIP call, "in-band" 
> DTMF signalling does not trigger an event in Asterisk; our PBX 
> possibly/probably does not create a SIP event for DTMF signalling.
> 
> Would you think that this may be the reason for our experienced 
> problems?

Asterisk knows of three different ways for DTMF signalling, in-band
being only one of those. There are also rfc2833 and info (SIP INFO)
signalling. You could try and set the dtmfmode= parameter in sip.conf to
one of those. voip-info.org has some info about it.

On the other hand it might be the case that your SIP PBX does _not_
generate SIP INFO or RFC messages but the DTMF signal is poor, not
allowing reasonable operation. I had that one with a SIP provider once,
effectively meaning I could not remote-control the voicebox.

Viel Erfolg,

Anselm