I have a customer that wanted a cheap control unit for his Techno Isel cnc router. I was able to reuue his existing cables and motors. I made db9 to db9 cable adapter pigtails and custom machined and built a 4 axis CNC system with the nearly burn out proof G540, a cooling fan, Home/limnit switch connectors, A lighted power switch. A ESTOP switch and an engage disengage switch. Also add were two connectors for 2 relay controlled receptacles capable of running 2 2HP motors ( if his AC source will handle it). I ran it for several hours running a torture test with no lost steps. The existing home and limit switch functions worked perfect with no false triggering of the limit switches. Best of all the control unit only cost him $599 plus shipping.