My program call CreateFile() to open a
port (like lpt1/com2), then, for a com
port, I uses API's like EscapeCommFunction()
,SetCommState(),etc.
But this does not work on NT 4 or 5.
I was told to write a device driver to talk
directly to port on NT.
My question is, what kind of driver should it
be? Is there any sample code I can start with?

Thanks a lot in advance!

Richard