Communication software in 7 lines of BASIC code. Quite simple. Joystick-port 2 is used for communication. Data is sent in groups of 4 bits. Up, down, left and right movement sets the bits 1, 2, 4 and 8. Fire tells bit have been sent, and to start 4 new bits. A byte is received after 2x Fire.

u: Up, d: Down, l: Left, r: Right, f: Fire

Order of ‘u’, ’d’ ,’l’ or ’r’ before next ‘f’ is not important. MSB is sent before LSB.

In my setup data is sent to the Joystick-port via a dtv2ser+usb interface and the Unix-software dtv2sertrans. The command line tool has an option to send “u”s, “d”s, “l”s, “r”s and “f”s via the option “joy stream”.

To create the “joystick-movement-stream”, I’ve created a lille program “bin2joy.py”.

BTW this is simplex, and 1-2 baud, so it’s just for fun, or if you miss a 1541 disk drive.