I know there are other options that are available to purchase for external Ethernet Motion control, but I am looking to make a custom solution.  I am mainly doing this because I have extra hardware laying around and I like the challenge.

I was wondering if anyone can explain the overall data flow with a External Ethernet Motion Controller? I was able to use the Plugin Wizard and I understand the overall  structure so far,  I just don't understand the what data being passed out of Mach.  How much is the controller doing?  Are they passing the various steps/planned trajectories and the controller is doing the acceleration itself or are they just passing the Raw Pulses Mach is generating for the Parallel port?

Pardon my ignorance, I am just starting to get into this.  Any help would be awesome. 

Thanks!