would there be any worries about using a couple resistors (to limit current) and a zener diode? Its a control signal so I'm not really worried about providing current elsewhere in the system.
I have a circuit involving a quadrature differential encoder and FPGA board. The FPGA board takes 5V logic as input but the supply to the quadrature encoder could be as high as 24V (to offset noise from a VFD nearby). I am already using a line receiver (a TI MC3486N) to combine the differential...
