Patent ID: 9140463
Filing Date: 2015-09-22
Classification: F24F

Abstract:
1. An indoor unit which supplies power to a load device externally connected to a power/communication line, the indoor unit comprising: a microcomputer to output a power application signal to supply the power to the load device; a duplicate power application prevention unit to interrupt the power application signal from the microcomputer when the power is simultaneously applied to the power/communication line by a different indoor unit, to prevent the power from being duplicately applied to the power/communication line; and at least two photo-couplers to optically isolate inputs of the duplicate power application prevention unit from a first power/communication line and a second power/communication line, wherein the power/communication line comprises the first power/communication line and the second power/communication line, and wherein the duplicate power application prevention unit comprises a first AND gate to receive a first signal which corresponds to a voltage on the first power/communication line and the first AND gate receives a second signal which corresponds to a voltage on the second power/communication line.