- Not connected (polarising pin)
- Floppy LED (active low)
- +5V power to keyboard
- Serial data from the keyboard (7812.5 baud, 8N1)
- Serial data to the keyboard
- Reset (active low)
Atari 800XL PC,
my Etsy store. You can order an Atari ST USB keyboard conversion kit below - the kit consists of the controller board, mountings and USB cable.