Hi Ray, I am trying to interface Yaskawa SGDH-02AE ServoPacks with Mach3 using Step/Direction using the SN75174 line driver interface. Do you have any idea what the ServoPack parameters should be? I tried the parameters you listed above in this thread for +-10v analog control. These settings had no effect on my results. Is the +-10v analog control considered Open-Collector with with an external power source? Do you have any idea what to do with pins 14 & 15 "Clear"? Any advice you can offer would be greatly appreciated.