[asterisk-users] Increase DTMF Tone Duration

[Steve Underwood]

Wilton Helm wrote:
> >The problem is simply the duration is too short (120ms), and the 
> remote IVR >seems to not detect them
>  
> That sounds like an IVR issue.  I've worked on some traditional PABXs 
> and even designed some DTMF receivers.  Any decent DTMF receiver 
> should be able to reliably decode 80 ms tones, and a really good one 
> can decode 40 ms.  120 ms should be a very generous duration.  I 
> shipped 80 ms duration to COs 20 years ago.
If you shipped detectors requiring an 80ms burst of tone to a telco 20 
years ago, they would have sent it back. They have never accepted more 
than a 50ms minimum tone burst, and many demand detection with just a 
40ms tone burst. Demanding >120ms is crazy. People just don't hold down 
the keys that long. You'd have horrible failure rates.

Regards,
Steve