Yes just had a look and C8 is where you would connect the Step/Dir signals to. The manual calls them Pulse/Dir but its the same thing. I didnt see any mention of single ended connections so if you do need differential it would be easy enough with a line driver, you can get them from US Digital and if I remember they are about $10.
C3 is where you woul;d connect your I/O, things such as drive enable, fault reset, drive enabled etc. As is normal with industrial drives the I/O is 24v so you would need to convert to/from the 5v that the computer uses, this can be done easily enough, relays etc
Hood