A board containing a matrix of sockets used to program a machine. Plugboards were widely used in punch card tabulating machines and early computers and were the predecessor to software programming. For example, each wire in the board directs a column of data from the punch card to a destination which could be a print column or a blank column in a card to be punched. A wire could also function as a switch by closing a circuit. See punch card
and accounting machine
Mounds of Spaghetti
This plugboard directed a card punch machine to read the cards in one hopper and punch holes in a blank cards in another hopper. Fields could be rearranged, and minor calculations could be performed. (Image courtesy of The Computer History Museum, www.computerhistory.org)
The Author of This Encyclopedia
In 1962, Alan Freedman was a Tabulating Technician; a fancy title for a punch card programmer. Proud to be photographed because it looks like "his" office at the Pennsylvania Sales Tax Bureau; however, he was really at one end of a 40-foot room.
Love that Pose
Twenty years later, Freedman finally did have his own office two blocks from Penn Station in New York.