PAR.BAS is a very simple program which runs under QBASIC (DOS) and
shows you in real-time the levels on the pins of your 
PC's parallel (printer) port. If you have a bidirectional port
(most modern PCs do) you can select input or output data mode.
In output mode, you can toggle each bit individually.  Useful for 
getting started with your hardware interfacing project.

Note: I've heard of people damaging their parallel ports. Don't let
more than a few mA flow through the output pins. (eg, connecting them
to ground and outputting a logic "HIGH" may cost you a new parallel
interface card. Or motherboard, if it's integrated (!)

Rolan Yang wrote PAR.BAS, I added a few lines for bidirectional ports.

jpb 5/3/97