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gen_packets - Man Page

Generate audio file for AX.25 frames.


gen_packets -o wav-file-out [ options ] [ text-file | - ]

wav-file-out is the result.  The -o option is required.

text-file may contain AX.25 packets in the standard monitoring format.  Use "-" to read from stdin.  If not specified, a default builtin message will be used.


gen_packets is a test application which converts text to AX.25 audio for testing packet decoders.

It is very flexible allowing a wide range of audio sample rates, data speeds, and AFSK tones.  It will even generate the scrambled signals commonly used for 9600 baud operation.


-a n

Signal amplitude in range of 0-200%.  Default 50.  Note that 100% is corresponds to signal peaks of +/- 16383 so we have plenty of headroom to avoid saturation.

-b n

Bits / second for data.  Default is 1200.

-B n

Data rate in bits/sec for first channel.  Standard values are 300, 1200, 2400, 4800, 9600.

300 bps defaults to AFSK tones of 1600 & 1800.

1200 bps uses AFSK tones of 1200 & 2200.

2400 bps uses QPSK based on V.26 standard.

4800 bps uses 8PSK based on V.27 standard.

9600 bps and up uses K9NG/G3RUH standard.

EAS for Emergency Alert System (EAS) Specific Area Message Encoding (SAME).


Force G3RUH modem regardless of data rate.


2400 bps QPSK compatible with Dire Wolf <= 1.5.


2400 bps QPSK compatible with MFJ-2400.

-X n

1 to enable FX.25 transmit.  16, 32, 64 for specific number of check bytes.

-I n

Enable IL2P transmit.  n=1 is recommended.  0 uses weaker FEC.

-i n

Enable IL2P transmit, inverted polarity.  n=1 is recommended.  0 uses weaker FEC.

-m n

Mark frequency.  Default is 1200.

-s n

Space frequency.  Default is 2200.

-r n

Audio sample Rate.  Default is 44100.

-n n

Generate specified number of frames with increasing noise.  (For built-in message only.)

-o file

Send output to .wav file.


8 bit audio rather than 16.


2 channels of audio rather than 1.


Variable speed with specified maximum error and optional increment.


gen_packets -o x.wav

With all defaults, a built-in test message is generated with standard Bell 202 tones used for packet radio on ordinary VHF FM transceivers.

gen_packets -o x.wav -g -b 9600

gen_packets -o x.wav -B 9600

Both of these are equivalent.  "-B 9600" automatically selects scrambled baseband rather than AFSK.

gen_packets -o x.wav -m 1600 -s 1800 -b 300

gen_packets -o x.wav -B 300

Both of these generate 200 Hz shift, 300 baud, suitable for HF SSB transceiver.

echo -n 'WB2OSZ>WORLD:Hello, world!' | gen_packets -a 25 -o x.wav -

atest x.wav

Read message from stdin and put quarter volume sound into the file x.wav.  Decode the sound file.

See Also

More detailed information is in the pdf files in /usr/local/share/doc/direwolf, or possibly /usr/share/doc/direwolf, depending on installation location.

Applications in this package: aclients, atest, cm108, decode_aprs, direwolf, gen_packets, kissutil, ll2utm, log2gpx, text2tt, tt2text, utm2ll