Almost everyone is familiar with the striped bars found on grocery and retail store items. These are bar codes, or more specifically, the Universal Product Code (UPC). UPC codes first appeared in stores in 1973 and have since revolutionized the sales industry.
The UPC code consists of ten pairs of thick and thin vertical bars that represent the manufacturer's identity, product size and name. Price information, which is not part of the bar code, is determined by the store. Bar codes are read by hand-held wand readers or fixed scanners linked to point of sale (POS) terminals.
Bar codes are also used for non-retail purposes. One of the earliest uses for bar codes was as an identifier on railroad cars. Organizers of sporting events also take advantage of bar code technology. For example, as runners of the Boston Marathon complete the 26 mi (42 km) course, they turn over a bar code tag that allows race officials to quickly tabulate results.
From 1965 through 1982, the United States Post Office experimented with optical character recognition (OCR) and bar code technology to speed up mail delivery. The Post Office now utilizes another type of bar code called the POSTNET bar code. Consisting of full and half height bars representing the zip-code and delivery address, the bar code allows mail to be sorted automatically at speeds of up to 700 pieces per minute.