I extracted three of these stepper controllers from the trash. A web search didn't net me anything regarding documentation. I'm not clear about what happens on terminals #1,2,& 3. Every things else seems pretty self explanatory. Terminal #1 is labeled +5VDC, #2 is DIR and #3 is CLOCK. From the circuit diagram it appears these are opto-isolated. Can I connect a RS232 signal to these or do I need another interface board to provide isolation from the computer. I guess my question is, "how do I connect a computer to this so I can use something like MACH3 to control steppers."