An air conditioning equipment having an in-room unit connected to one end of the refrigerant pipes and an out-room unit connected to the other end of the refrigerant pipes. The air conditioning equipment includes signal coupling portions which are respectively disposed at both end parts of the refrigerant pipes. Each of the signal coupling portions couples an alternating current (AC) control signal to the refrigerant pipes and exhibits a predetermined impedance with respect to an AC electric signal. The configuration of the air conditioning equipment brings forth the advantages that the electrical insulation devices used in the prior art are dispensed with, and the signal transmissions between the in-room unit and the out-room unit can be performed by a simple apparatus configuration.