Abstract: A plurality of air conditioning units (20, 20) are daisy-chain connected to each other by a switching hub (31) provided in an outdoor unit (30). An integrated transmission line (10A) and internal/external transmission lines (10B) are connected to each other by a gateway (32) connected to the switching hub (31) so as to be capable of separating data transmission.

Abstract: A plurality of air conditioning units (20, 20) are daisy-chain connected to each other by a switching hub (31) provided in an outdoor unit (30). An integrated transmission line (10A) and internal/external transmission lines (10B) are connected to each other by a gateway (32) connected to the switching hub (31) so as to be capable of separating data transmission.

Abstract: A setting button (53) for setting an option for changing a driving mode is provided in any one of indoor control units (3) belonging to each of refrigerant control systems (12, 13). An outdoor control unit (2) sets to each indoor control unit (3) a system number of the refrigerant control system (12, 13) to which each indoor control unit (3) belongs. The indoor control unit (3) outputs an option holding signal and a system signal of the system number. A integral controller (4) is provided with a system indicating button (6a) for indicating the option and the refrigerant control system (12, 13). Further, the integral controller (4) is provided with an option indicating lamp (HSM) for indicating the option and a system indicating lamp (HLM) for indicating the refrigerant control system (12, 13).