A driving system for an automatic sliding door includes a driver and a rack and pinion mechanism. The pinion is selectively attachable to the driver in a first position to cause sliding movement of the door in the first direction and in a second position to cause sliding movement of the door in the second direction. A device for indicating whether a driving system is suitable for driving a sliding door includes a first end, a region including one or more calibrations; and a second end. The first end is adapted to be pulled by a user. The second end is adapted to be selectively and detachably attached to one of the calibrations. The region is located between the first end and the second end.