Gordon - This is a great project, and you're making progress!
You will first have to add a few lines of code at the start of the sbitx program execution to open the /dev/ttyUSB0 serial port. Program start main() can also be found in sbitx_gtk.c Look for the string VER_STR? .
Then, have a look at the ui_tick function in the sbitx_gtk.c file. You'll find a function call a few lines down - cmd_exec(remote_command) . Your interim solution may include a new call that looks something like cmd_exec(serial_command) - which would be a way to demonstrate that your serial commands can be interpreted just like telnet commands.
After that, possibly create a new function called serial_command_exec(serial_command) with this new function coded to respond to the commands that an IC-7300 accepts.
Your idea to just plug in a Serial to USB converter is an excellent way to add a serial port to the sBitx.
73; Steve, N3SB
