Abstract: An interfacing system for selectably interfacing signals to a computer, or other control apparatus such as a numerical control system, from either of alternative transducers which provide position indicative signals differing in format. A system according to the invention is useful for interfacing signals to a control system from either a resolver or an encoder and includes a digital counter whose output count, irrespective of the transducer type, is indicative of the monitored object's position. A data latch connected between the control or receiving instrumentation and the counter holds a count at an appropriate time and then provides a transfer of the position indicative count to the receiving instrumentation. Circuitry is included for automatically causing the counter to function as a reversing counter or as a reference counter, depending on the type of transducer signals to be interfaced.