[asterisk-app-dev] DTMF/other uses question

[Joshua Colp]

Tickling Contest wrote:
> I have a DTMF related question. I understand how to reap DTMF using
> Asterisk, and related application environments, for example, ARI. See as
> an example
> https://wiki.asterisk.org/wiki/display/AST/ARI+and+Channels%3A+Handling+DTMF.
>
> While, sending DTMF over a landline phone is slow; I was wondering if
> there is anyway to send it faster over PSTN for applications using
> smartphone apps as the SIP UA, so that my PBX connected via a SIP trunk
> into an Asterisk PBX, can retrieve more information faster (e.g.,
> retrieve a 40-digit DTMF quicker than 1 second). For starters, is it
> even possible? if so, how have you achieved it? My thinking is, "if fax
> can do this, there has to be other ways of using DTMF..."

Fax does not use DTMF, it uses a few different other methods to encode 
data. As for being fast there's a minimum amount of time that a DTMF 
digit can be for most detectors to recognize it as DTMF, so you can't 
really blast DTMF that fast.

>
> Do common libraries like PJSIP allow this? What API calls are involved,
> if so?

We don't use PJMEDIA for that so I can't comment.

-- 
Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org