The other day I modified my Arduino-TNC, which was already a modified version of the Mobilinkd Arduino-TNC. You can find their version here:
http://www.mobilinkd.com/2014/09/11/arduino-kiss-tnc/
And you can read my modifications post here:
https://alaskalinuxuser3.ddns.net/2022/10/27/arduino-tnc-part-1-hardware/
Essentially, what I …