A switching circuit provides multi-way control of the connection of a relatively high current load to a source of power by the momentary closing of any one of a number of switches at remote locations. A control current in the milliampere range is fed to the remote switches at a voltage having either...http://www.google.com/patents/US4525634?utm_source=gb-gplus-sharePatent US4525634 - Alternating current switching device
