I've been trying to confirm serial port operation with Altirra/x64 2.40 (800 OS-B NTSC / 48K). What I'd like to do ideally is redirect the screen print output (typically using POKE'ing X,Y cursor screen location) to the serial port. Failing that a method of just sending the same print screen data to the serial port.
Before doing that of course (if possible!), I'd like to test the serial port emulation in Altirra using R: How is this configured to test the functionality with a terminal emulator such as Putty?