Teletypewriter Exchange Service

The Teletypewriter Exchange Service (TWX) was an American telecommunication system that allowed subscribers to exchange textual communications and data directly. Introduced by the American Telephone and Telegraph Company (AT&T) in 1931, it was a switched teleprinter network. Initially, switching was manual, but it was automated after World War II. TWX operated using teleprinters, which are devices with a typewriter keyboard and a printer. Each keystroke generated coded electrical impulses sent over a transmission line. In 1970, Western Union acquired TWX from AT&T. However, TWX and the similar Telex system could not communicate directly due to differences in coding schemes and transmission speeds. Western Union linked them via processing centers that translated between the two systems. By the 1980s, the rise of high-speed digital communication, particularly fax, led to a decline in TWX usage. Western Union sold its Telex network to AT&T in 1990, and both AT&T and British Telecoms announced they would no longer directly provide telex services in 2008, though smaller companies continued to offer it.123