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Re: DTMV v3

From: Cullen Jennings (fluffy) <fluffy@cisco.com>
Date: Wed, 9 Jan 2013 03:41:35 +0000
To: Alexey Aylarov <alexey@zingaya.com>
CC: Roman Shpount <roman@telurix.com>, Harald Tveit Alvestrand <harald@alvestrand.no>, "public-webrtc@w3.org" <public-webrtc@w3.org>
Message-ID: <C5E08FE080ACFD4DAE31E4BDBF944EB11336A6EF@xmb-aln-x02.cisco.com>

On Jan 8, 2013, at 11:40 AM, Alexey Aylarov <alexey@zingaya.com> wrote:

> It's around 200ms between Russia and US
> BR,
> Alexey

I wonder if we are talking about different numbers here because I'm not sure what you mean between Russia and US. 

The number I am looking for is: when connected to the PSTN in Russia, what is the minimum gaps of silence that are required between two DTMF tones so that the two tones are detected as two different tones instead of just one long tone? Can you track down the specification that governs that in Russia? ITU-T Q.24 table A-1 calls this "pause duration" and the largest value it has is 70 ms for Australia but it does not have a value for Russia  (never mind that 4733 claims the max value is in the A-1 table is 40 ms - I have no idea how 4733 got that idea)

I'm looking at some of our configs and if it is 200 ms for Russia, well we are not leaving that much space and it seems like a bunch of the cordless phone vendors would also need to have different configuration than they are using. Now it could easily be that we have that messed up  

Thanks, Cullen
Received on Wednesday, 9 January 2013 03:42:02 UTC

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