70 lines
2.4 KiB
Groff
70 lines
2.4 KiB
Groff
.\"
|
|
.\" Copyright (c) 1999 Hellmuth Michaelis. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" $Id: dtmfdecode.1,v 1.6 1999/12/13 22:11:55 hm Exp $
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.\" last edit-date: [Mon Dec 13 22:53:13 1999]
|
|
.\"
|
|
.\"
|
|
.Dd February 15, 1999
|
|
.Dt DTMFDECODE 1
|
|
.Os
|
|
.Sh NAME
|
|
.Nm dtmfdecode
|
|
.Nd decodes DTMF tones from A-law audio data
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
utility
|
|
is part of the isdn4bsd package and is used to detect DTMF tones in the
|
|
audio stream.
|
|
.Pp
|
|
It reads audio G.711 A-Law coded data from stdin and outputs the detected
|
|
numbers values as ASCII charcters to stdout.
|
|
.Pp
|
|
The detector is implemented as 8 narrow band-pass filters realized with
|
|
an integer double-cross recursive algorithm. Various ad-hoc methods are
|
|
employed to provide hysteresis and anti-bounce for the detected signals.
|
|
.Sh EXAMPLES
|
|
The command:
|
|
.Bd -literal -offset indent
|
|
dtmfdecode < beep.al
|
|
.Ed
|
|
.Pp
|
|
will print a "1" to stdout.
|
|
.Sh STANDARDS
|
|
ITU Recommendations G.711
|
|
.Sh AUTHORS
|
|
.An -nosplit
|
|
The
|
|
.Nm
|
|
utility was written by
|
|
.An Poul-Henning Kamp Aq phk@FreeBSD.org .
|
|
This man page was written by
|
|
.An Hellmuth Michaelis Aq hm@FreeBSD.org .
|