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

[Tilghman Lesher]

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, 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.

-- 
Tilghman Lesher
Digium, Inc. | Senior Software Developer
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