A Transmission System for Teletypewriter Exchange Service

O M E E T the growing needs of business organizations, particularly those operating on a nationwide basis with branches at widely separated locations, there has developed in the United States an extensive use of private line telegraph service. This trend has been accelerated by the perfection of the teletypewriter, which makes it possible for regular office employees to transmit and receive communications without a large amount of special training. Some of these private line teletypewriter networks have been provided with switching facilities to permit the customer to set up connections between his various offices or groups of offices as desired. As these arrangements were perfected and as the public gained experience with the teletypewriter method of communication, a demand developed for a teletypewriter service in which all connections would be set up on a switched basis similar to that provided for spoken conversation by the telephone system. To meet this demand teletypewriter exchange service or as it is usually called, TWX service, was inaugurated by the Bell System in November 1931. Briefly described, teletypewriter exchange service makes available to subscribers a complete communication system for the written word, consisting of: (a) (b) (c) Teletypewriters for sending and receiving, installed on the customers' premises with a connection to a nearby switching center. Transmission channels interconnecting all of the switching centers. Teletypewriter switchboards for connecting the subscribers' stations and loops to each other or to the inter-city transmission channels and for making through connections between inter-city circuits.