The Picturephone System: Customer Switching Systems

Customer switching systems furnish service to Bell System customers in every business category. Such systems range in size from only two or three telephones up to many thousands of extension telephones. Because of the potential value of face-to-face communications to business customers, facilities have been made available so that they can subscribe to Picturephone service as part of customer switching system service. The customer switching category includes several basic types of service. One type, known as Private Branch Exchange (PBX) service, is obtained from switching equipment located on the customer's premises. It permits connections to be set up quickly between the telephone users at the same business location, without the need for connecting to, and switching through, a central office. PBX systems also permit the customer's employees to place and receive calls to and from the central office via switches which provide a form of concentration when fewer central office paths are needed than customer stations. In PBX service, all calls from the central office, and some to the central office, are completed with the aid of the customer's operator, or attendant, who provides many useful services such as accepting calls for the concern and directing them to particular employees, aiding in the placing of outgoing calls, and screening them when 553