Abstract: A normally open reed switch mounted on a door jamb is closed by a magnet in a chain-lock keeper when the door is closed. A pole piece, which functions as a bolt on the end of the chain, engages in the keeper and shunts the flux of the permanent magnet so that the reed switch is not effected by the flux, and assumes its normally open condition if the bolt is seated home in the keeper.

Abstract: An electrical system for controlling energy output within an enclosed space, such as a motel room, including a door switch adapted to be controlled by the opening and closing of the door and a latch switch adapted to be controlled by the operation of a door latch. The system may control several types of electrical devices, such as a heating and air-conditioning unit, illuminating devices and electrical outlets within the room.The system is so designed that when the door is closed and latched from the inside all electrical devices will function normally. When the room is unoccupied, with the door closed and the inside latch unlatched, the electrical devices will be turned off or switched to a low-energy background level.