[Linked Image from i.imgur.com]

I got it to print some data, but it seems to drop characters while it's printing, probably some handshaking problem.

It should print PRINT "DATA TO PRINTER" and have DATA TO PRINTER underneath each line.

But it's a little closer 8-)

The Apple parallel interface sends 8 bit data, and the high bit is set, I just cleared the high bit and the printer liked that data a lot better.