[asterisk-dev] ASTERISK - DTMF Inband Handling

[Matt Fredrickson]

On Wed, Jul 12, 2017 at 10:47 AM, bala murugan <fightwithme at gmail.com> wrote:
> Hi ,
>
>  can anyone provide answers or comments on the below
>
>  1.   What is the expected minimum and maximum silence duration between the
> dtmf tones.

I think that depends on how you're playing DTMF tones within Asterisk.
For tones utilized in the case of sending call address data to setup
the call, the answer is dependent on the channel driver.  For tones
that are bridged between calls that are already up and active, you can
potentially have variable length tones, depending on where the DTMFs
are coming from.  If you're using an application in Asterisk to play
tones depending on the underlying API the answer might be different as
well.  Which case are you concerned about?

> 2. mindtmfduration = 80msec in /etc/asterisk/asterisk.conf what is the
> significance of this parameter ? .  Is there any maxdtmfduration or
> highwatermark configuration or limitation in handling the DTMF tone's

If a passed through DTMF event on a bridged call that's already up
receives a dtmf indication that is shorter than the mindtmfduration,
Asterisk will extend the length of the tone to be at least
mindtmfduration milliseconds long.

> 3. can it handle the DTMF tones  ranging in the 180-210 ms duration . The
> reason is we are experiencing DTMF issue and all the tones that sent to
> asterisk are in this range.

I can't think of a reason why that would be an issue.

-- 
Matthew Fredrickson
Digium, Inc. | Engineering Manager
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA