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From: Matti Aarnio <matti.aarnio@zmailer.org>
To: "David D. Hagood" <wowbagger@sktc.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [Asterisk] DTMF noise
Date: Fri, 10 Jan 2003 08:52:18 +0200	[thread overview]
Message-ID: <20030110065218.GE27709@mea-ext.zmailer.org> (raw)
In-Reply-To: <3E1E06A3.8050607@sktc.net>

On Thu, Jan 09, 2003 at 05:32:51PM -0600, David D. Hagood wrote:
> Well, I found out that while we have the DTMF test tape at work, it is 
> exactly that - a cassette tape that is copyrighted. So, no easy/legal 
> way to make it available for testing...

What does such tape contain ?
 - DTMF tones buried in various degrees of distortions,
   which should be decodable ?
 - DTMF tones buried in varying noises which should not be
   decodable ?
 - Other multi-tone signals which should not decode ?

For the last, I know of cases where test was done by playing a radio 
station on the decoder for 2-3 days, and seeing when does it trigger
DTMFs (if ever).

For that matter, the Linux kernel ISDN audio DTMF detection is exactly
of the last variant.

/Matti Aarnio

  reply	other threads:[~2003-01-10  6:43 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20030107140012$1b66@gated-at.bofh.it>
     [not found] ` <20030107150006$4896@gated-at.bofh.it>
2003-01-07 19:08   ` Thomas Tonino
2003-01-07 22:46     ` Roy Sigurd Karlsbakk
2003-01-08  7:51       ` Thomas Tonino
2003-01-08 12:43         ` David D. Hagood
2003-01-08 13:04           ` Matti Aarnio
2003-01-08 15:49           ` Wolfgang Fritz
2003-01-08 16:30             ` Wolfgang Fritz
2003-01-08 19:48             ` Andrew McGregor
2003-01-08 22:19             ` Jamie Lokier
2003-01-09 12:51             ` David D. Hagood
2003-01-09 13:31               ` Wolfgang Fritz
2003-01-09 23:32                 ` David D. Hagood
2003-01-10  6:52                   ` Matti Aarnio [this message]
2003-01-10 12:42                     ` David D. Hagood
2003-01-10 12:03                 ` Roy Sigurd Karlsbakk
2003-01-08 20:22           ` Thomas Tonino
2003-01-09 12:42             ` David D. Hagood
2003-01-07 13:55 Roy Sigurd Karlsbakk
2003-01-07 14:49 ` [Asterisk] " Mark Spencer

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