Machine-switching apparatus. Historical photograph of an automated machine-switching apparatus at a telephone exchange. At a telephone exchange, wires and switches (forming what is called a switchboard) are used to re-route telephone calls to their destinations. Automated exchanges began to be developed in the early 1900s. They eliminated the need for human switchboard operators to complete the connections required for a telephone call. The technology used electromechanical systems and telephones were equipped with a dial with which a caller transmitted the destination telephone number to the automatic switching system. This photograph is from an archive of images dating from the 1860s to the 1920s, collected for 'The Pageant of America: A Pictorial