Apparatus for conserving energy in a building

摘要

Apparatus for turning off power-consuming appliances in rooms of a building having a private automatic branch exchange telephone system includes computer-controlled means at the exchange central periodically to apply short bursts of audio-frequency oscillations to telephone lines going to rooms in which power can be conserved. Detecting means in each room connected to the room telephone line provide an output on receipt of a burst which operates a line relay in the room, disconnecting power from the appliance in the room, for a predetermined time period greater than the time period between the periodic application of bursts at the exchange central.