[asterisk-dev] DTMF detection and generation code

[Vahan Yerkanian]

Steve Underwood wrote:
> With most cellular base stations each press of the buttons on the phone 
> produces a fixed length DTMF pulse, with a fixed silence following it. 
> If you press keys in quick succession, they are buffered up, and played 
> out as tones at the pace the base station sees fit. Typically they make 
> the tones very long, for some reason. 0.5 seconds in many cases. I think 
> your application sounds broken by design. I've been through this before, 
> trying to build things which require rhythmic input. It just doesn't 
> work, unless your application is limited to plain old analogue land line 
> phones.

DTMF buffer is another useful thing - currently digits sent too fast are 
guaranteed to be skipped. Ironically, I never get a double or skipped 
digits from cellular networks - these send DTMFs with loooong durations 
as the developers have accounted for lossy nature of the cellular 
technology.

Vahan

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