[Asterisk-Users] European and/or US DTMF Tones?

[Steve Underwood]

Angus Berry wrote:

>My business is somewhat trans-atlantic. Does anyone know if Asterisk's
>DTMF processing is:
>
>a) European OR US
>
>b) European AND US
>
>c) It's hardware dependent you fool.
>
>d) here's a better answer
>
>thanks :-)
>  
>
The DTMF specs vary between countries, but not in ways that really 
matter to anyone. The variations are just things like how off frequency 
the tones may be, the minimum signal level at which they must be 
detected, and so on. For practical purposes DTMF is universal. The DTMF 
in * passes a test suite applicable to most countries. With the wonders 
of open source, you can even try the test suite yourself, if you want 
(less the part that requires BellCore's copyright talk-off tests data - 
I can give you a copy of the data I used, but only if you own a copy of 
BellCore's tapes).

Regards,
Steve