NAME¶
minimodem - software audio Bell-type or RTTY FSK modem
SYNOPSIS¶
minimodem --tx [
options]
{baudmode}
minimodem --rx [
options]
{baudmode}
DESCRIPTION¶
minimodem is a command-line program which generates (or decodes) audio
modem tones at any specified baud rate, emulating an old Bell-type or
radio-teletype FSK modem. The tones can be played to (or recorded from) the
PulseAudio system or to an audio file.
minimodem can be used to transfer data between nearby computers using an
audio cable (or just via sound waves), or between remote computers using
radio, telephone, or another audio communications medium.
TX/RX MODE¶
- -t, --tx, --transmit, --write
- transmit mode: generate audio tones
- -r, --rx, --receive, --read
- receive mode: decode audio tones
OPTIONS¶
- -a, --auto-carrier
- automatically detect mark and space frequences from
carrier
- -c, --confidence threshold
- set receive confidence threshold (0.0 to 1.0, default
0.6)
- -8, --ascii
- ASCII 8-N-1
- -5, --baudot
- Baudot 5-N-1.5
- -f, --file filename.wav
- encode or decode an audio file (extension sets audio
format)
- -b, --bandwidth {rx_bandwidth}
- -M, --mark {mark_freq}
- -S, --space {space_freq}
- -T, --txstopbits {m.n}
- -q, --quiet
- Do not report CARRIER / NOCARRIER or signal analysis
metrics.
- -V, --version
- print program version
{baudmode}¶
The required
{baudmode} parameter may be any floating-point value to
specify a baud rate, or the string "rtty". The
{baudmode}
also implies certain other parameter defaults depending on the rate, including
standard (or at least reasonable) default mark and space tone frequencies.
- 1200
- : Bell202 1200 bps --ascii
- 300
- : Bell103 300 bps --ascii
- rtty
- : RTTY 45.45 bps --baudot --txstopbits 1.5
- {any floating point value N}
- : Bell-like N bps --ascii
EXAMPLES¶
- minimodem --tx 100
- Transmit 100 baud tones from one computer ...
- minimodem --rx 100
- and receive 100 baud tones on another nearby computer.
- minimodem --rx --auto-carrier rtty
- Decode amateur radio RTTY signals (listen near 14.085
MHz).
- minimodem --tx 0.5
- Experiment with very low baud rates (works in noisy
conditions).
- minimodem --tx 12000
- Experiment with very high baud rates works (works with
audio files).
NOTES¶
minimodem does not decode AX.25 framed packets.
minimodem does not support modem control ("AT") commands, nor
does it produce DTMF telephone dialing tones.
VERSION¶
This page documents
minimodem version 0.8.1. The latest version is
available at <
http://www.whence.com/minimodem>.
AUTHOR¶
minimodem was written by Kamal Mostafa <kamal@whence.com>.
COPYRIGHT¶
Copyright © 2011 by Kamal Mostafa <kamal@whence.com>. License GPLv3+:
GNU GPL version 3 or later <
http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO
WARRANTY, to the extent permitted by law.
