NAME
multimon - program to decode radio transmissions
SYNOPSIS
multimon [options] [input_file]
DESCRIPTION
This manual page documents briefly the multimon command. This manual
page was written for the Debian GNU/Linux distribution because the
original program does not have a manual page.
The multimon software can decode a variety of digital transmission
modes commonly found on UHF radio. A standard PC soundcard is used to
acquire the signal from a transceiver. The decoding is done completely
in software. Currently, the following modes are supported:
* AX.25
o 1200 Baud AFSK
o 2400 Baud AFSK (2 variants)
o 4800 Baud HAPN
o 9600 Baud FSK (G3RUH)
* POCSAG
o 512 Baud
o 1200 Baud
o 2400 Baud
* Miscellaneous
o DTMF
o ZVEI
o SCOPE
An arbitrary set of the above modes may run concurrently on the same
input signal (provided the CPU power is sufficient), so you do not have
to know in advance which mode is used. Note however that some modes
might require modifications to the radio (especially the 9600 baud FSK
and the POCSAG modes) to work properly.
AX.25 - Amateur Packet Radio protocol datagram format
POCSAG (Post Office Code Standards Advisory Group) is a common paging
transmission format.
DTMF - Dual Tone Multi Frequency. Commonly used in in-band telephone
dialing.
ZVEI- The German Electrical and Electronic Manufacturers’ Association -
paging tone format.
SCOPE - show samples in a rudimentary oscilloscope display on an X
server.
Multimon does not decode Morse code signals.
OPTIONS
-t <type>
input file type (any other type than raw requires sox)
allowed types: raw aiff au hcom sf voc cdr dat smp wav maud vwe
-a <demod>
add demodulator
-s <demod>
subtract demodulator
Where <demod> is one of: POCSAG512 POCSAG1200 POCSAG2400 EAS AFSK1200
AFSK2400 AFSK2400_2 HAPN4800 FSK9600 DTMF ZVEI SCOPE
The -a and -s options may be given multiple times to specify the
desired list of demodulators.
EXAMPLE
Decode signal modulations from a sound file /tmp/message.wav without
using a SCOPE display:
multimon -s SCOPE -t wav /tmp/message.wav
With no input file specified, the program listens directly to the sound
card using the /dev/dsp interface. So to decode (only) DTMF tones on
the sound card input:
multimon -a DTMF
NOTICE
Please note that monitoring commercial services may be prohibited in
some countries, this software should therefore only be used to monitor
the amateur radio service.
SEE ALSO
gen(1) http://www.qsl.net/kb9mwr/projects/pager/Two-
Tone%20Pager%20Decoding%20Using%20Multimon.pdf
BUGS
The DTMF and ZVEI decoders have more frequent spurious detection
reports.
AUTHOR
This manual page was written by A. Maitland Bottoms
<bottoms@debian.org>, for the Debian GNU/Linux system (but may be used
by others).
June 19, 2000