[VoIP] DTMF question

[Shane Young]

You should be able to do DTMF all the way through, end to end, inband  
if everything is set correctly on your SIP devices.

IAX, on the other hand, always handles DTMF out of band.

If Asterisk sees that one side is in-band (the Sipura) and the other  
side (someone else's switch) is out of band, it should send the DTMF  
out of band.



Quoting John Novack <jnovack at stromberg-carlson.org>:

> Others may know more, but I believe Asterisk doesn't play well with
> inband DTMF
> For that you need a real switch!
>
> John Novack
>
>
> Jayson Smith wrote:
>> Hi,
>> This isn't what I want. I think it'd be cool to use actual inband DTMF. Such
>> that, when I hit a button, the other end of the call can hear the tone for
>> as long as I keep it held down, and any imperfections, etc. That's what's
>> inband DTMF is supposed to be, right? Where no digital translation happens,
>> and the two ends of the call just send DTMF directly to each other?
>> Thanks.
>>
>> ----- Original Message -----
>> From: "John Novack" <jnovack at stromberg-carlson.org>
>> To: "Jayson Smith" <ratguy at bellsouth.net>; "Voice Over IP Tandem for Analog
>> Switches" <voip at ckts.info>
>> Sent: Tuesday, April 03, 2007 2:25 PM
>> Subject: Re: [VoIP] DTMF question
>>
>>
>>
>>> I use:
>>> dtmfmode=rfc2833
>>> for my SIP devices, and have no problem
>>> I do believe that is the suggested mode for use with Asterisk, and may
>>> solve your DTMF problem
>>>
>>> John Novack
>>>
>>>
>>> Jayson Smith wrote:
>>>
>>>> Hi all,
>>>> Got a puzzling one for you guys. I recently got three Sipura SPA-2000
>>>>
>> units,
>>
>>>> and am using one, and like it. Just for the heck of it, I set
>>>> dtmfmode=inband for both lines in sip.conf, and have both lines set for
>>>> inband DTMF in the SPA. Still, calling one line from the other via my
>>>> Asterisk system, when I hit a touchtone on either phone, the other gets
>>>>
>> a
>>
>>>> tiny blip of the original tone, then, once I let up on the button, a
>>>> regenerated, fixed-duration touchtone is heard. In other words, as far
>>>>
>> as I
>>
>>>> can tell, inband DTMF isn't really working. My codec choice is Ulaw, so
>>>>
>> that
>>
>>>> shouldn't be a problem. Any thoughts?
>>>> Thanks.
>>>>
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>>>>
>>>>
>>>>
>>
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>>
>>
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>

--Shane
+1-821-7311 CNET