I am really trying to get a decent wireless system with my arduino + amateur radio. I found this IC that decodes FSK signals, and was wondering if it could help me with decoding AFSK 1200baud signals. The IC is the NJM2211. I have no idea how the IC works, how to get it timed correctly, or what it outputs out of that pin.

Should I go this direction? Would this IC help me?

  • \$\begingroup\$ You might like: argentdata.com/catalog/… \$\endgroup\$
    – JonnyBoats
    Feb 25, 2012 at 5:58
  • \$\begingroup\$ Do I see an avr ic on that thing? Wish they'd just release the code for it... Would really love to see how they pulled it off cleanly. \$\endgroup\$
    – Kyle
    Feb 25, 2012 at 6:02
  • \$\begingroup\$ The TCM3105 is another old FSK modem chip that was very commonly used with microcontrollers. Here is an article from QST that compares the TCM3105 with a slightly different replacement, the MX614. This example shows connecting directly to a PCs RS-232 port. \$\endgroup\$
    – Paul
    Mar 30, 2016 at 20:32

1 Answer 1


Actually you can decode the signals in software using the Arduino. See Arduino TNC.

The software to do this is open source, BeRTOS.

Here is the hardware interface:

enter image description here


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