At the turn of the 20th century, the Post Office Department relied entirely on antiquated mailhandling operations, such as the "pigeonhole" method of letter sorting, a holdover from colonial times. Although crude sorting machines were proposed by inventors of canceling machines in the early 1900s and tested in the 1920s, the Great Depression and World War II postponed widespread development of post office mechanization until the mid-1950s. The Post Office Department then took major steps toward mechanization by initiating projects and awarding contracts for the development of a number of machines and technologies, including letter sorters, facer-cancelers, automatic address readers, parcel sorters, advanced tray conveyors, flat sorters, and letter mail coding and stamp-tagging technology.
Post Office Sorting Machines
As a result of this research, the first semi-automatic parcel sorting machine was introduced in Baltimore in 1956. A year later, a foreign-built multiposition letter sorting machine (MPLSM), the Transorma, was installed and tested for the first time in an American post office. The first American-built letter sorter, based on a 1,000-pocket machine originally adapted from a foreign design, was developed during the late 1950s. The first production contract was awarded to the Burroughs Corporation for 10 of these machines. The machine was successfully tested in Detroit in 1959 and eventually became the backbone of letter-sorting operations during the 1960s and 70s.
Post Office Cancelers
In 1959, the Post Office Department also awarded its first volume order for mechanization to Pitney-Bowes, Inc., for the production of 75 Mark II facer-cancelers. In 1984, more than 1,000 Mark II and M-36 facer-cancelers were in operation. By 1992, these machines were outdated and began to be replaced by advanced facer-canceler systems (AFCS) purchased from ElectroCom L.P. The AFCSs process more than 30,000 pieces of mail per hour, twice as fast as the M-36 facer-cancelers. AFCSs are more sophisticated too: they electronically identify and separate prebarcoded mail, handwritten letters, and machine-imprinted pieces for faster processing through automation.
Post Office Optical Character Reader
The Department's accelerated mechanization program began in the late 1960s and consisted of semi-automatic equipment such as the MPLSM, the single position letter sorting machine (SPLSM), and the facer-canceler. In November 1965, the Department put a high-speed optical character reader (OCR) into service in the Detroit Post Office. This first-generation machine was connected to an MPLSM frame and read the city/state/ZIP Code line of typed addresses to sort letters to one of the 277 pockets. Each subsequent handling of the letter required that the address be read again.