.\" Hey, EMACS: -*- nroff -*- .\" First parameter, NAME, should be all caps .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection .\" other parameters are allowed: see man(7), man(1) .TH MINIMODEM 1 "August 19, 2012" .\" Please adjust this date whenever revising the manpage. .\" .\" Some roff macros, for reference: .\" .nh disable hyphenation .\" .hy enable hyphenation .\" .ad l left justify .\" .ad b justify to both left and right margins .\" .nf disable filling .\" .fi enable filling .\" .br insert line break .\" .sp insert n+1 empty lines .\" for manpage-specific macros, see man(7) .SH NAME minimodem \- software audio Bell-type or RTTY FSK modem .SH SYNOPSIS .B minimodem --tx .RI [ options ] .I {baudmode} .br .B minimodem --rx .RI [ options ] .I {baudmode} .SH DESCRIPTION .B 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 system audio (PulseAudio or ALSA) or to an audio file. .PP .B 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. .SH "TX/RX MODE" .TP .B \-t, \-\-tx, \-\-transmit, \-\-write transmit mode: generate audio tones .TP .B \-r, \-\-rx, \-\-receive, \-\-read receive mode: decode audio tones .SH OPTIONS .TP .B \-a, \-\-auto-carrier automatically detect mark and space frequences from carrier .TP .B \-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). .B \-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). .TP .B \-8, \-\-ascii ASCII 8\-N\-1 .TP .B \-5, \-\-baudot Baudot 5\-N\-1.5 .TP .B \-f, \-\-file filename.wav encode or decode an audio file (extension sets audio format) .TP .B \-b, \-\-bandwidth {rx_bandwidth} .TP .B \-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). .TP .B \-M, \-\-mark {mark_freq} .TP .B \-S, \-\-space {space_freq} .TP .B \-T, \-\-stopbits {m.n} Sets the number of stop bits (default is 1.0, or 1.5 for rtty). .TP .B \-q, \-\-quiet Do not report CARRIER / NOCARRIER or signal analysis metrics. .TP .B \-R, \-\-samplerate {rate} Set the audio sample rate (default rate is 48000 Hz). .TP .B \-A, \-\-alsa Use ALSA as the audio output system instead of the default PulseAudio (depending on build configuration options). .TP .B \-\-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). .TP .B \-\-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). .TP .B \-\-rx-one Quit after the first carrier/no-carrier event (applies to \-\-rx mode only). .TP .B \-\-benchmarks Run and report internal performance tests (all other flags are ignored). .TP .B \-V, \-\-version print program version .SH {baudmode} The required \fI{baudmode}\fR parameter may be any floating-point value to specify a baud rate, or the string "rtty". The \fI{baudmode}\fR also implies certain other parameter defaults depending on the rate, including standard (or at least reasonable) default mark and space tone frequencies. .TP .B 1200 : Bell202 1200 bps \-\-ascii .TP .B 300 : Bell103 300 bps \-\-ascii .TP .B rtty : RTTY 45.45 bps \-\-baudot \-\-stopbits 1.5 .TP .B {any floating point value N} : Bell-like N bps \-\-ascii .SH EXAMPLES .TP .B minimodem --tx 100 Transmit 100 baud tones from one computer ... .TP .B minimodem --rx 100 and receive 100 baud tones on another nearby computer. .TP .B minimodem --rx --auto-carrier rtty Decode amateur radio RTTY signals (listen near 14.085 MHz). .TP .B minimodem --tx 0.5 Experiment with very low baud rates (works in noisy conditions). .TP .B minimodem --tx 12000 Experiment with very high baud rates (works with audio files). .SH NOTES .B minimodem does not decode AX.25 framed packets. .PP .B minimodem does not support modem control ("AT") commands, nor does it produce DTMF telephone dialing tones. .SH VERSION This page documents .B minimodem version @PACKAGE_VERSION@. The latest version is available at . .SH AUTHOR .B minimodem was written by Kamal Mostafa . .SH COPYRIGHT Copyright \(co 2011-2012 by Kamal Mostafa . License GPLv3+: GNU GPL version 3 or later . .br This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.