asterisk users - Sep 2009 - DTMF end '1' has duration 57 but want minimum 80, emulating on IAX2/a16-q1-9657

Hello,

I have a 3 server asterisk configuration where one asterisk (say A) (v
1.4.25) has a digiuim card connected to E1 from which calls are routed
to another asterisk server  (B) (1.6.0.9) over SIP trunk from which
calls get routed to third server (C) (1.6.0.9) via IAX trunk.
SIP clients are connected to third server. A is the PSTN termination
server, B runs the menu and AGI and C is where SIP clients connect.
SIP clients can also dial outside and call goes like C -> B -> A ->
PSTN.

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?

with regards,

raj

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
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