jhs@MITRE-BEDFORD.ARPA (04/03/86)
I'm not an ST owner but I will speculate that the printer port is a standard "PIA" or 68000-family equivalent. (Actually they may well use the 6800 family chip, as it ought to be entirely compatible.) If so, the same wires are both an input and an output. Also, the device control register information can be looked up in a standard PIA data sheet and you will be able to figure out how to program it to be an input. On the 800XL, the joystick ports are the same way. They are tied to a PIA and are usually used for input. But they can just as well be written to as outputs for special purposes - like hooking up a parallel printer without paying for an expensive interface! -John Sangster jhs@mitre-bedford.arpa