Codabar is a linear barcode symbology developed in 1972 by Pitney Bowes Corp. It and its variants are also known as Codeabar, Ames Code, NW-7, Monarch, Code 2 of 7, Rationalized Codabar, ANSI/AIM BC3-1995 or USD-4.
Although Codabar has not been registered for US federal trademark status, its hyphenated variant Code-a-bar is a registered trademark.
It was designed to be accurately read even when printed on dot-matrix printers for multi-part forms such as FedEx airbills and blood bank forms, where variants are still in use as of 2007. Although newer symbologies hold more information in a smaller space, Codabar has a large installed base in libraries. It is even possible to print Codabar codes using typewriter-like impact printers, which allows the creation of a large number of codes with consecutive numbers without having to use computer equipment. After each printed code, the printer's stamp is mechanically turned to the next number, as for example in mechanical mile counters.