will it fix the problem I posted in this thread?
http://www.cnczone.com/forums/showthread.php?t=75784 (G540 debug problem)
A smoothstepper is a device that takes commands from Mach3 via USB and sends step and direction pulses through it's own built in port(s).
I don't know for sure, but I do think it would fix your problem.
Mach3 2010 Screenset
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)