I'm getting called for dinner, so I'll have to break this off and return later with a fresh outlook. I'm not sure what else to try (my original condition). The problem seems to be logical, i.e., some sort of misalignment between Mach3 and the port.
I went to Rosewill's site to check for a newer driver, only to find their downloadable version is an earlier one than I have installed. Just an added bit of confusion. Too bad I don't have any other parallel port devices, e.g., a printer, to try.
Many thanks for your help.
Charley