Automatic call recording and accounting in the SATT system

When the first automatic telephone office was placed in public service at La Porte, Ind., in 1892, automatic switching and subscriber dialing became established facts. During the years following this notable event in the history of telephone communication, Automatic Electric Company through constant research and development of switching equipment and operating methods expanded the field of automatic switching from local exchange areas to suburban and toll networks. By 1910 operator toll dialing was introduced whereby originating toll operators were enabled to complete calls to automatic stations in distant towns by toll dialing.1 Operator toll dialing was then expanded to provide switching of toll circuits through tandem and switching centers. During the period from 1920 to 1940, several regional automatic toll switching networks were established in various parts of the United States and Canada.