Impulse sender (dial) used in panel telephone exchange systems, made by the Western Electric Company, United States, 1915.
The panel system of automatic telephone exchange was developed in the USA by Western Electric, the manufacturing arm of AT&T. Unlike Strowger, the selector mechanism was power-driven and the switching banks were laid out in tall longitudinal 'panels'. Calls were dialled in the usual way. The system was designed to allow inter-working between automatic and manual exchanges and was therefore suitable for the largest towns and cities. Although proposed for use in Britain, the panel system was rejected by the Post Office in favour of Strowger.