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Re: Min DTMF Gap

From: Roman Shpount <roman@telurix.com>
Date: Fri, 17 Jan 2014 12:43:34 -0500
Message-ID: <CAD5OKxuxNNc-78u7KsxO6BsjiQkXf7GHvLB-VS6UaoV6SnfE7A@mail.gmail.com>
To: Harald Alvestrand <harald@alvestrand.no>
Cc: "public-webrtc@w3.org" <public-webrtc@w3.org>
On Fri, Jan 17, 2014 at 1:42 AM, Harald Alvestrand <harald@alvestrand.no>wrote:

>  On 01/17/2014 01:43 AM, Roman Shpount wrote:
> I was the person who asked for this change.
>  Based on http://www.itu.int/rec/T-REC-Q.24-198811-I/en Annex A, valid
> tone duration is 40 ms and up. Valid gap duration is 30 ms (minimal for
> Japan) and up to 70 ms minimum in Australia. So, my suggestion was to keep
> defaults at their current values but allow to set minimal values to minimal
> possible legal values (40 ms tone and 30 ms gap). My justification is that
> DTMF is a legacy interop feature and it should be able reproduce any legal
> DTMF string which can occur in the wild by modifying the JavaScript
> parameters.
> Current text:
> The duration parameter indicates the duration in ms to use for each
> character passed in the tones parameters. The duration cannot be more than
> 6000 ms or less than 70 ms. The default duration is 100 ms for each tone.
> The interToneGap parameter indicates the gap between tones. It *must* be
> at least 50 ms. The default value is 50 ms.
> So you're suggesting that 70 ms change to 40 ms, and "at least 50 ms"
> change to "at least 30 ms"?
This is exactly what I am suggesting.

>  I don't have a problem with that - I think it's risky for an app to use
> bursts so short that they are not required to be detected in some
> jurisdictions .... but that's the app's problem, not mine.
I agree completely. Most of the people should leave the configuration
settings at their default values. If they are changing this, they should
know what they are doing.
Roman Shpount
Received on Friday, 17 January 2014 17:44:04 UTC

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