[asterisk-users] DTMF end '1' has duration 57 but want minimum 80, emulating on ?IAX2/a16-q1-9657

[Tzafrir Cohen]

On Sat, Sep 19, 2009 at 09:17:31AM -0500, Tilghman Lesher wrote:
> On Saturday 19 September 2009 01:07:54 Rajkumar S wrote:
> > I have an occasional problem where DTMF is not recognized, ie if
> > clients type a digit while in menu the system does not register it.
> >
> > In my C server I saw a log line like this today:
> >
> > DTMF end '1' has duration 57 but want minimum 80, emulating on
> > IAX2/a16-q1-9657
> >
> > Is the above message an indication of this problem? How can I fix it?
> 
> It isn't evidence of this problem, but it might be indicative of it.  What
> this message says is that the DTMF lasted for 57ms, but Asterisk normally
> doesn't detect DTMF that lasts for under 80ms, 

Isn't 40ms the minimal time for a valid dtmf digit?

> so it is increasing the
> duration of the DTMF to compensate (because as a digital signal, DTMF is
> reliable, but when sent as audio, it might not be).  What it probably
> indicates is that the DTMF sent to your system is _incredibly_ short, and if a
> DTMF detector is employed, it's possible that the DTMF audio is simply too
> short to be reliably detected.

-- 
               Tzafrir Cohen
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