[Asterisk-Users] Outband DTMF on i4l modem

[Clif Jones]

Best of luck on getting an answer, I have posted several times with the 
same question.
Unfortunately my time to reverse engineer this problem right now is low 
but my
temporary solution's cons are pushing me to jump into the code and fix 
the problem.
As a workaround you can set your Cisco phones to disable out-of-band 
DTMF and
on Asterisk set the sip.conf entries for these phones to use inband 
DTMF.  You will
be able to get external IVR to work but you will probably have to use 
something like
G.711 so the quality is hight enough.  The codec usage depends on your 
configuration
and you may be able to get away with some compression.  I currently have 
some Cisco
7960's for phones and an Audiocodes 4-port FXO gateway installed.  When 
using
out-of-band DTMF, Asterisk DTMF functions worked fine.  I could not hear 
DTMF
between the Cisco 7960s (who really cares).  The real problem was that I 
could not
get DTMF relayed from the Cisco 7960 to PSTN via Asterisk and the 
Audiocodes.
This is where I have to sit down with a packet sniffer and debug logs to 
see what is going
on with the RTP.  I need to know if the problem is in Asterisk relaying 
the phone events
containing DTMF or if it is the Audiocodes not generating DTMF tones on 
the analog side.
Hope this rambling helps.  Maybe it will prompt someone else to chime in 
with a solution. :)

Matthew Enger wrote:

>Hello,
>
>I am setting up 2 ISDN 4 linux cards and have had great success now that
>I have got over the initial problems with : and / characters.
>
>
>The only problem I am experiencing now is the sending of DTMF tones over
>the line to a remote IVR system.
>
>If I dial SIP (Cisco 7905 and 7940) to a number over the line, no DTMF
>tones are heard. I dialed my own home phone and tried it, no matter
>which button i pressed, no tones came out.
>
>However when I dial voicemail, the buttons work fine. 
>
>Is this a problem with asterisk not putting the tones onto i4l?
>
>Thanks,
>
>Matthew Enger <menger at xi.com.au>
>Xintegration
>
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