VAR-SOM-AM43 RS232-Port
From Variscite Wiki
VAR-SOM-AM43 - RS-232 Port
1. Perform a loopback at RS-232 port by shorting pins 2 & 3 in J8 on the carrier board, or connect to another computer.
2. Start minicom.
minicom -D/dev/ttyO2 -b115200 -8
3. Type a few characters at the minicom and see that the loopback is working.