Abstract: Apparatus for validating a card having positioned thereon a plurality of redundant encoded blocks of data readable by moving the card past a reader and for controlling the movement of such a card whose validity is to be determined. A card transporter moves a card along a predetermined path. A reader senses each block of data on the card as it moves forward along the path from an entry position to a dwell or escrow position and supplies an electrical signal representative of the data in each block. A card validator responsive to this signal compares data derived from at least one block thereof with a preselected set of data in making the validity determination. The validator includes circuitry for combining the data from at least one block with a prior set of data to produce a stored resultant set of data, and for comparing it with a preselected set of data and for supplying an indication of card validity if these sets of data are identical.