On 2014-01-18 00:23, Roman Shpount wrote:
>
> I now suggest that we follow the ETSI standard and set 70 tone 70
> gap fixed with no adjustment possibility.
>
>
> This will be extremely undesirable. First of all, you do need to
> generate long DTMF tones (there are IVR features that are activated by
> DTMF tone of half a second or longer). Second, and this was the
> original reason for my request to Cullen to change these parameters,
> there are a lot of legacy interop scenarios with opposite requirements
> (some need long tones, some need short tones, some need gaps of the
> right minimal length). Let the defaults be safe for typical DTMF use
> case, but let the application developer be able to generate any legal
> DTMF tone if it is needed. If app developer decides to change these
> optional settings, it is his responsibility to make sure that they
> will work for his use case. There is no point to reinvent DTMF
> standards here -- let's set the minimums to currently accepted minimums.
If you see a need for settings, I do not mind having that possibility.
The 40 ms minimum is for detection at the receiving end, so it would be
logical to set the possible transmission timing minimum slightly higher.
/Gunnar