Ahhhh... those schematics reminds me of the good times
Personally I'd have used the RS232 UART with a MAX232 chip to convert back and forth to TTL levels, because with that setup you'll monopolize your printer port
*edit* while you're at it why not put a cheap microcontroller for the serial, LED and LCD logic such as a 80C552 ? You can reprogram it countless times, it's an EEPROM. And it can be programmed in C, even
@Leagle:
you silly