Thanks Robert!

I figured out what was wrong with my serial luaprinter, it was that I used a char variable instead of a u8 and it was converting 128-255 into a negative number. (That's what I get for growing up with Pascal CHAR types 8-) It's got to be unsigned char.

void serial_luaprinter_device::rcv_complete()
        u8 recchar = get_received_char();

so now the Amiga ImagewriterII driver can do this:

[Linked Image from]

Oddly, printing out of the serial port seems faster than out of the parallel port.