Dosbox doesn't link the serial or parallel ports to the emulator so you won't be able to use them to communicate with anything.

gee, I hope you can understand what i said 😀

I do now after spending many hours looking through old messages.
Still, that would be a great way of saving my old programs that
will not run on xp.
Thanks,
Ray

I to am trying to use serial i/o using:
[directserial]
# directserial -- Enable serial passthrough support.
# comport -- COM Port inside DOSBox.
# realport -- COM Port on the Host.
# defaultbps -- Default BPS.
# parity -- Parity of the packets. This can be N, E or O.
# bytesize -- Size of each packet. This can be 5 or 8.
# stopbit -- The number of stopbits. This can be 1 or 2.

but not sure how to modify qb45 to use!
Help!
Ray

You can try qemu or Bochs if you need direct LPT access. Google for them.