PC program to read encoders

Hello everyone:

I've been looking for a program that would use a laptop
PC as a digital readout. I found a free 4 axis program
with a simple interface circuit. The program and circuit
is located at http://www.mindspring.com/~wgray1/dro.html
Everything looks like it should work, but I just can't get
mine working. Has anyone else tried this DRO. If it works
it would be a great way to add readouts to many devices.

Thanks Terry