Description
The IBM 533 Input-Output Unit, announced on July 2, 1953, was a punched card reader and punch that served as the primary input-output unit for the IBM 650 computer. It had two independent card paths, one for reading and one for punching. IBM cards were fed face down, 12-edge first. All 80 columns could be read and punched by the computer as numeric data, but alphanumeric reading was severely limited on the basic 650 and require special control panel wiring.
