Provided is a communication system for an air conditioner including a housing and a control board accommodated in the housing. The communication system includes: a communication conversion unit accommodated in the housing and configured to acquire a required electric signal from the control board and to convert the electric signal into a digital signal for wire transmission; a cable having a first end connected to the communication conversion unit, the cable being drawn out of the housing to outside; and an antenna unit connected to a second end of the cable located outside the housing, the antenna unit being configured to establish wireless communication with a base station.