Abstract: Photo-optical apparatus for reading a label or the like carrying a label code readable in the form of a binary code characterized by presence or absence of optically detectable indicia at predefined zones of predetermined dimension. The apparatus includes optical sensors disposed adjacent to a path so as to be responsive to indicia carried by the label travelling in a direction such that the indicia is disposed in first and second tracks parallel to the direction of label travel. A programmed microprocessor is responsive to the state of the sensor outputs for detecting the direction of label travel and reversals of the direction of travel, and for selectively controlling entry and output of the label code to and from a data storage register such that upon completion of a read cycle the order of data significance can be determined independently of direction of travel of the label through the path past the sensors and independently of the left or right side mounting of sensors with respect to label travel path.