xenial (1) minimodem.1.gz

Provided by: minimodem_0.23-1_amd64 bug

NAME

       minimodem - general-purpose software audio FSK modem

SYNOPSIS

       minimodem --tx [options] {baudmode}
       minimodem --rx [options] {baudmode}

DESCRIPTION

       Minimodem  is a command-line program which decodes (or generates) audio modem tones at any specified baud
       rate, using various framing protocols.  It acts  a  general-purpose  software  FSK  modem,  and  includes
       support  for  various  standard  FSK  protocols  such  as Bell103, Bell202, RTTY, TTY/TDD, NOAA SAME, and
       Caller-ID.

       Minimodem can play and capture audio modem tones in real-time via the system audio device, or in  batched
       mode via audio files.

       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

{baudmode}

       The required {baudmode} parameter may be any floating-point value to specify a baud rate, or any  of  the
       special keywords listed below.  The {baudmode} also implies certain other parameter defaults depending on
       the rate, including standard (or at least reasonable) default mark and space tone frequencies.

       {any floating point value N}
              : Bell202-style at N bps --ascii

       1200   : Bell202 1200 bps --ascii

       300    : Bell103 300 bps --ascii

       rtty   : RTTY 45.45 bps --baudot --stopbits 1.5

       tdd    : TTY/TDD 45.45 bps --baudot --stopbits 2.0

       same   : SAME 520.83 bps --startbits 0 --stopbits 0 --sync-byte 0xAB
                   NOAA Specific Area Message Encoding (SAME) protocol

       callerid
              : Bell202 1200 bps Caller-ID (MDMF or SDMF) protocol

       uic-train
              : UIC-751-3 600 bps train-to-ground message protocol

       uic-ground
              : UIC-751-3 600 bps ground-to-train message protocol

OPTIONS

       -a, --auto-carrier
              Automatically detect mark and space frequences from carrier.

       -i, --inverted
              Invert the mark and space frequencies (applies whether the frequencies are defaults, discovered by
              --auto-carrier, or specified manually).

       -c, --confidence min-confidence-threshold
              Set  receive confidence minimum threshold (default 1.5).  The "confidence" value is a metric based
              primarily on the SNR (signal-to-noise ratio) of the received signal.  This value acts  as  an  FSK
              decoder  "squelch"  control.   Increase  to  accept only very clean signals (up to INFINITY, but a
              value around 5.0 is more practical).  Decrease to accept partial decoding of noisy  signals  (down
              to a minimum value of 1.0).  (This option applies to --rx mode only).  -l, --limit max-confidence-
              search-limit Set receive confidence maximum search limit (default 2.3).  The "confidence" value is
              as  described above.  This value acts as a performance vs. analysis quality control.  Increase (up
              to INFINITY) for a more pedantic analysis and higher  CPU  usage.   Decrease  (down  to  the  min-
              confidence-threshold) for a sloppier analysis, with lower CPU usage.  (This option applies to --rx
              mode only).

       -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}

       -v, --volume {tx_amplitude or 'E'}
              Sets the generated signal amplitude (default is 1.0).  As a special case useful for  testing,  the
              value  'E'  sets  the amplitude to the very small value FLT_EPSILON.  (This option applies to --tx
              mode only).

       -M, --mark {mark_freq}

       -S, --space {space_freq}

       --startbits {n}
              Sets the number of start bits (default is 1 for most baudmodes).

       --stopbits {n.n}
              Sets the number of stop bits (default is 1.0 for most baudmodes).

       --sync-byte {0xXX}
              If this option is used, initial carrier acquisition will be suppressed until  after  one  or  more
              consecutive data frame(s) containing this value are received.  This can be used to synchronize the
              stream for protocols which include a fixed preamble byte.   (This  option  applies  to  --rx  mode
              only).

       -q, --quiet
              Do not report CARRIER / NOCARRIER or signal analysis metrics.

       -R, --samplerate {rate}
              Set the audio sample rate (default rate is 48000 Hz).

       -A, --alsa[={plughw:X,Y | X,Y | X }]
              Use  ALSA  as  the  audio  output  system  instead  of  the default PulseAudio (depending on build
              configuration options).  The ALSA device alias "default" is used, if  a  specific  device  is  not
              specified.  For example, the following options all select ALSA device #1, sub-device #0:
               --alsa=plughw:1,0  --alsa=1,0  -A1

       --lut={tx_sin_table_len}
              Minimodem  uses a precomputed sine wave lookup table of 1024 elements, or the size specified here.
              Use --lut=0 to disable the use of the sine wave lookup table.  (This option applies to  --tx  mode
              only).

       --float-samples
              Generate  32-bit floating-point format audio samples, instead of the default 16-bit signed integer
              format (applies to --tx mode only; --rx mode always uses 32-bit floating-point).

       --rx-one
              Quit after the first carrier/no-carrier event (applies to --rx mode only).

       --binary-output
              Print received data bits as raw binary output using characters '0' and '1'.  The bits are  printed
              in  the  order they are received.  Framing bits (start and stop bits) are omitted from the output.
              (This option applies to --rx mode only).

       --binary-raw {nbits}
              Print all received bits (data bits and any framing bits) as raw binary output using characters '0'
              and '1'.  Framing bits are not interpreted, but simply passed through to the output.  The bits are
              printed in the order they are received, in lines {nbits} wide.  So in order to display a  standard
              8-N-1 bitstream (8 databits + 1 start bit + 1 stop bit), use "--binary-raw 10"
               or a multiple of 10.  (This option applies to --rx mode only).

       --print-filter
              Filter  the received text output, replacing any "non-printable" bytes with a '.' character.  (This
              option applies to --rx mode only).

       --tx-carrier
              When transmitting from a blocking source, keep a carrier going while waiting for more data.

       --benchmarks
              Run and report internal performance tests (all other flags are ignored).

       -V, --version
              print program version

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 -a rtty
              Decode amateur radio RTTY signals (listen near 14.085 MHz).

       minimodem --rx same
              Decode NOAA SAME protocol emergency alert transmissions, e.g.
              <http://en.wikipedia.org/wiki/Specific_Area_Message_Encoding>.

       minimodem --tx 0.5
              Experiment with very low baud rates (works in noisy conditions).

       minimodem --tx 12000
              Experiment with very high baud rates (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   0.23.    The   latest   version   is   available   at
       <http://www.whence.com/minimodem>.

AUTHOR

       minimodem was written by Kamal Mostafa <kamal@whence.com>.

       Copyright © 2011-2016 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.

                                                  June 10, 2013                                     MINIMODEM(1)