(1) (TELetypewriter EXchange) An international, dial-up data communications service administered in the U.S. by AT&T, MCI and other providers. Developed in the U.S. and other European countries in the 1930s, it was the first data communications service that used typewriter-like terminals (teletypewriters). Prior to Telex, telegrams and cablegrams were the primary method for delivering a text message. By the 1960s, Telex became a worldwide, real-time, data communications service. Although diminishing each year, Telex is still used for commerce in more than 200 countries.Telex started out transmitting Baudot code at 50 bps. Although upgraded, it is still a low-speed data service. It was originally administered worldwide by various carriers and the local PTTs. Western Union handled the U.S., and in 1971, purchased and integrated the Bell System's TWX service. AT&T acquired Western Union's Telex service in 1991.