[Asterisk-Users] dtmf tone clamping in calls to external ivr

[Klaus-Peter Junghanns]

Hi Mark,

sorry to say this, but you wont be able to forward dtmf with isdn4linux.
Try to get your hands on an AVM Fritz card (or any other isdn card with
capi drivers) and use chan_capi.

best regards

Klaus
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Klaus-Peter Junghanns

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Am Mo, 2004-04-26 um 17.43 schrieb Mark Mickan:
> Hello,
> 
> I'm having trouble working out how to send DTMF tones to an external
> IVR.  My system has an analog phone connected to a TDM400P card, a SIP
> software phone (Zultys LIPZ4) and is connected to a BRI in Australia
> with a NETjet-S card.  I'm using ISDN4Linux and a 2.4.25 kernel patched
> with the ISDN audio patch from Traverse (which allows the card to do
> voice).
> 
> DTMF works fine between the analog phone and the SIP phone - I can hear
> the tones on the SIP phone when I use dtmfmode=inband and I can see them
> with dtmfmode=info, and I hear them on the analog phone.
> 
> When I bring the ISDN link into the picture, such as to call to my phone
> banking, it doesn't recognise any tones.  I have also tested this by
> dialling my mobile (via the ISDN link) and it sounds like Asterisk is
> clamping the tones - I hear the very first part of the tone then the
> call is muted for the remaining duration of the tone.  I _can_ hear the
> tones on my analog phone when I press them on the mobile, however, so it
> seems the problem is only in the one direction.
> 
> I've been grepping the mailing list archives and found Pauline
> Middelink's isdn-dsp patch (which I've applied in an attempt to solve
> this problem - I've now got "features=dtmf,noquelch" in my modem.conf),
> but that seems to relate to digits coming _from_ the ISDN _to_ Asterisk,
> not the other way around.  Looks like some people have run into my
> problem before, but I cannot find any conclusions in the list archives.
> 
> Can anyone help?
> 
> Thanks in advance,
> Mark