Re: Converting a Sherline Mill to Mach3 with oddball drivers.
From my web page at:
techref.massmind.org/techref/io/steppers.htm
Control Signals: The stepper motor controller typically accepts two inputs from an external source: Step and Direction. The Direction signal set the direction of rotation and each pulse on the Step signal causes the controller to move the motor one step in that direction. The controller translates these signals into different patterns of current flow in the coils, which result in the moment of the motor. The Step signal may be called: Clock, CLK+, Pluse, etc.. and Direction may be called DIR, CCW+, CW/CCW, but they are still just carrying Step and Direction information.
So based on that, I would guess that C is your clock or Step line and D is your Direction. You can't cause harm by getting those backwards; it just won't work correctly. Power and ground, of course, will fry things if you get them attached wrong, but they should be clear.
James hosts the single best wiki page about steppers for CNC hobbyists on the net:
http://www.piclist.com/techref/io/steppers.htm Disagree? Tell him what's missing! ,o)