Abstract: A linear position indicating system utilizing a fixed chain (20) which engages a pinion (32) connected to a mechanical input of an encoder (26) for providing position information. Encoder (26), supported on a relatively movable cross slide (14), provides an output signal indicative of the position of crosslide (14) relative to member (12) from which it is supported. Idlers (34, 36) are provided to guide the chain (20) around pinion (32) to ensure a large contact of approximately 180.degree.. Proximity switches (50, 52) are disposed for detecting when crosslide (14) is near its travel limits. The distance between switches (50, 52) is adjustable so they can be set at a precise separation. A counter (72) is provided for counting pulses as crosslide (14) moves between switches (50, 52). The output of counter (72) is used along with the know separation between switches (50 52) for calibrating the output of encoder (26).