Dear Parick,

AFAIK the Apple LW ][ is a XOn/XOFF protocol printer.
You stated the settings to be:
reports the settings:

baud:           9600
parity:         none-mark
handshake:      DSR/DTR
data bits:      standard/7
stop bits:      1

So I think handshake should be XON/XOFF instead of DSR/DTR.

Sorry for my poor english, being just a simple Dutch-man,

Erik Ulijn
Delft,
The Netherlands.