[Asterisk-Users] DTMF and ivr systems

[Doug Crompton]

I am using an SPA-3000 and after using Ulaw (G711) on my * to FXO side
(not FXS) it seems to work fine. I believe there is a problem with * and
DTMF that is being worked on and there should be something new to (try) in
the 1.4 release this summer. I don't think you mentioned your hardware. I
think this works differently  depending on the device. When I used
RFC-2833 and AUTO on my SPA-3000 FXO side, I got the short muted blip of
DTMF you mentioned. Changing to INBAND now gives at least a 250ms+
duration, which has been long enough to work with anything I have
tried.

The reason that * is checking/muting DTMF is that it has to look for
transfer and other codes to process. So this is the other gotcha. You
cannot use transfer or any other features because even with inband * seems
to mute when using this - I.E. if your transfer feature is #9, when you
hit the # key it will mute and the # key will never get through. I believe
the correct behavior would be to wait and see if the second key was sent
in a certain time and if not then send the orginal key. Rather tricky but
it does not work in the current *. So I do not use any features that use
the DTMF keys.

So to summarize.... INBAND, Ulaw, on FXO and not use of DTMF features and
it should work. Turning off feaures means no Tt, etc in dial command. I do
transfers or parking, if needed via switch hook. Hopefully this will be
fixed and I can go back to rfc-8322 and also have my features back in the
future.

It also really helps to call yourself, say to a cellphone, and listen for
this behavior!

Doug

On Sat, 1 Jul 2006, Monty Lilburn wrote:

> Hi,
>
> I too am experiencing the same problem you have.
>
> I am using inband DTMF processing with ULaw (G711) and like you I notice
> that Asterisk seams to be passively listening to the line waiting to hear
> a DTMF.  When it hears a DTMF it mutes the handset and
> regenerates my original DTMF (in a very short burst) which often gets
> missed by the remote party.  This is especially true for IVR systems.
>
>  	I haven't come across a configuration option that keeps Asterisk
> from muting the handset and regenerating the original DTMF.  Perhaps if
> Asterisk saw that the active channel was using inband processing with G711
> it could leave everything alone and just let the user's dtmf go through
> unfettered!
>
> If this isn't possible for some technical reason I wonder if there is a
> configuration option that allows the user to set the duration of the
> regenerated dtmf?
>
> Maybe a developer will see this and can comment.
>
> Best regards,
>    Monty
>
>
> On Thu, 29 Jun 2006, Shane wrote:
>
> > Hello,
> >
> > Ther's probably a simple answer to this but I've searched
> > around and haven't located anything as yet.  Is there a way
> > to have DTMF tones passed through Asterisk without it
> > messing with them?  I am using a tdm21b card and when I
> > call an ivr system from the telephone handset (routed over
> > sip or iax2) such as telebanking, the ivr has trouble
> > recognizing tones.  When I tested this with a remote party,
> > I was told tones were breaking up.  For example, a long
> > press would result in a click, some silence and a small
> > dtmf on the remote end.  Triggering a speed dial didn't go
> > well either as he heard only a few tones.  I have
> > dtmfmode=inband in sip.conf and have tried relaxdtmf=yes in
> > zapata.conf.
> >
> > I realize Asterisk does need to detect dtmf for things like
> > call parking but can it just pass the audio to the other
> > side with no regard for whether it's dtmf digits?  IE. long
> > press results in long tone, etc.
> >
> > Best,
> > Shane
> >
> >
> >
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"Those that sacrifice essential liberty to obtain a little temporary safety
 deserve neither liberty nor safety."  -- Ben Franklin (1759)

****************************
*  Doug Crompton	   *
*  Richboro, PA 18954	   *
*  215-431-6307		   *
*		  	   *
* doug at crompton.com        *
* http://www.crompton.com  *
****************************