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multimon-ng is the successor of multimon. It decodes the following digital transmission modes:

• POCSAG512 POCSAG1200 POCSAG2400
• FLEX
• EAS
• UFSK1200 CLIPFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3
• HAPN4800
• FSK9600
• DTMF
• ZVEI1 ZVEI2 ZVEI3 DZVEI PZVEI
• EEA EIA CCIR
• MORSE CW
• X10

multimon-ng can be built using either qmake or CMake:

mkdir buildcd buildqmake ../multimon-ng.promakesudo make install

mkdir buildcd buildcmake ..makesudo make install

The installation prefix can be set by passing a 'PREFIX' parameter to qmake. e.g:qmake multimon-ng.pro PREFIX=/usr/local

So far multimon-ng has been successfully built on:

• Arch Linux
• Debian
• Gentoo
• Kali Linux
• Ubuntu
• OS X
• Windows (Qt-MinGW build environment, Cygwin, and VisualStudio/MSVC)
• FreeBSD

Files can be easily converted into multimon-ng's native raw format usingsox. e.g:

sox -t wav pocsag_short.wav -esigned-integer -b16 -r 22050 -t raw pocsag_short.raw

GNURadio can also generate the format using the file sink in input modeshort.

You can also "pipe" raw samples into multimon-ng using something like:

sox -t wav pocsag_short.wav -esigned-integer -b16 -r 22050 -t raw - | ./multimon-ng -

As a last example, here is how you can use it in combination with RTL-SDR:

rtl_fm -f 403600000 -s 22050 | multimon-ng -t raw -a FMSFSK -a AFSK1200 /dev/stdin

A more advanced sample that combinesrtl_fm,flac, andtee to split the output fromrtl_rm into separate streams. One stream to be passed toflac to record the audio and another stream to for example an application that does text parsing ofmulimon-ng output

rtl_fm -s 22050 -f 123.456M -g -9.9| tee>(flac -8 --endian=little --channels=1 --bps=16 --sample-rate=22050 --sign=signed - -o~/recordings/rtlfm.$EPOCHSECONDS.flac -f)| multimon-ng -v 0 -a FLEX -a FLEX_NEXT -t raw /dev/stdin

1. You can pass-l tortl_fm for the squelch level, this will cut the noise floor so less data gets encoded by flac and will significantly reduce the file size but could result in loss of signal data.This value must be tuned!
2. Flac uses-8 here, if you run an a resource constraint device you may want to lower this value
3. The Flac-o argument value contains$EPOCHSECONDS to make unique files when this gets restarted

To replay the recorded flac file to multimon-ng (requires sox):

flac -d --stdout ~/recordings/rtlf/rtlfm.1725033204.flac | multimon-ng -v 0 -a FLEX_NEXT -t flac -

qmake multimon-ng.pro PREFIX=/usr/localmakemake install INSTALL_ROOT=/