AT&T facilities and services

This paper describes the U. S. telecommunications network with particular emphasis on aspects that are of importance to data- and computer-oriented services. The major portion of this network is owned and operated by the AT&T Company and the associated operating units of the Bell System as well as the independent branch of the industry. The services which the telephone network offers for data today depend in large part on transmission and switching systems which have evolved over the past decades primarily for voice transmission. An understanding of the history of the growth of the network and its facilities is useful background for the description of the current data services given later in this paper. After the current data services have been outlined, plans for AT&T's new Digital Data System, which utilizes a network of digital carriers for data transmission, will be described.