IBM 31 Alphabetical Duplicating Punch
IBM 31 Alphabetical Duplicating
Punch
Electromechanical machines to punch, tabulate and sort cards at high speed were at the heart of information processing through the late 1950s. The Type 31 alphabetical duplicating key punch was introduced by IBM in 1933, and it recorded alphabetic information on tabulating cards for later printing, together with numerical data, on an alphabetical accounting machine. The Type 31 automatically ejected one card and fed another in half a second.