Sorting was a major activity in most facilities that processed data on punched cards using unit record equipment.
(IBM 1962) Cards are normally passed through the sorter face down with the bottom edge ("9-edge") first.
The holes sensed in that column together with the settings of the sorter controls determine which pocket the card is to be directed to.
This directing is done by slipping the card into a stack of metal strips (or chute blades) that run the length of the sorter feed mechanism.
The 083 and 084 sorters recognized these multiple-digit or multiple-zone punches, sorting them to the error pocket.
[11] The punched cards and brushes in these modern sorters have been replaced with image sensors (cameras) and computer vision technology, but their form and operation remain essentially identical to that of their historical predecessors.