Umbrella Technologies has designed an interface board specifically for KFLOP called UMAX. It contains most everything one might need for a typical 3 axis mill conversion using stepper drivers. About a dozen input conditioning circuits for limits and proximity sensors, four relay outputs, driver enables, a special EStop circuit, and more.
Only $99 for the basic board.
Please check it out at:
http://umaxcnc.com/
TK