Ray, Thanks for the reply. I now have two drives running under MACH3 control. I was setting the Pulse Train "1" in the zero position not the one of Pn000. When I figured this out everthing started to work properly. I built a buffered two axis breakout board that seems to be working. I am now gathering the parts to make a four axis breakout board. Do you recommend turning the servo on (S/on) on when the system powers on or controlling it some other way? Some of my servo drives have 24v holding brakes. I was thinking about using one of these to drive the Z-axis. Do you know a way to release the brake just prior to a Z-axis move?