Hi, thanks for reply. The initial board is a Conqueror MPC 5 which appears to control the original Ash boards. The initial cable is a serial with: 2, RCD; 3, TXD; 5, Ground (7, RTS and 8, CTS are not joined - could be wrong cable). Mach 3 uses parallel ports, my electronics aren't good enough to know if a parallel to serial conversion is possible (although I can etch and make up any board). Thanks, Ray