An air conditioner having an indoor unit and an outdoor unit connected through power lines (PL1, PL2) and communication lines (CL1, CL2), at least one of the indoor unit and the outdoor unit comprising: a communication unit (150, 240) configured to perform communication; a switching unit (160, 250) configured to transmit voltage of a signal between the communication lines (CL1, CL2) and the communication unit (150, 240) when the switching unit (160, 250) is turned on, and configured to prevent the voltage of a signal from being transmitted through the switching unit (160, 250) when the switching unit (160, 250) is turned off; a voltage distribution unit (170, 260) configured to distribute voltage from the communication lines (CL1, CL2) to the communication unit (150, 240) when the switching unit (160, 250) is turned off; wherein the switching unit (160, 250) and the voltage distribution unit (170, 260) are connected to a communication terminal assembly (CT1, CT2), and the communication terminal assembly (CT1, CT2) is connected to the communication unit (150, 240) through the switching unit (160, 250) and the voltage distribution unit (170, 260), wherein the communication terminal assembly (CT1, CT2) is connected to the communication lines (CL1, CL2) to receive a signal a voltage adjustment unit (190, 280) provided between the communication unit (150, 240) and the communication terminal assembly (CT1, CT2), the voltage adjustment unit being configured to prevent burning of the communication unit (150, 240) due to line connection errors by being configured to adjust the voltage applied to the communication unit (150, 240) and transmit the adjusted voltage to the communication unit (150, 240), such that when voltage exceeding a designated voltage is applied to the voltage adjustment unit (190, 280) through the power lines (PL1, PL2) connected by error to the first communication unit (150, 240), the voltage adjustment unit (190, 280) adjusts the applied voltage to the designated voltage or less; and a control unit (130, 220) configured to turn the switching unit (160, 250) off when the at least one of the indoor unit and the outdoor unit enters a standby mode, and turn the switching unit (160, 250) on based on the voltage distributed by the voltage distribution unit in the standby mode. a communication unit (150, 240) configured to perform communication; a switching unit (160, 250) configured to transmit voltage of a signal between the communication lines (CL1, CL2) and the communication unit (150, 240) when the switching unit (160, 250) is turned on, and configured to prevent the voltage of a signal from being transmitted through the switching unit (160, 250) when the switching unit (160, 250) is turned off; a voltage distribution unit (170, 260) configured to distribute voltage from the communication lines (CL1, CL2) to the communication unit (150, 240) when the switching unit (160, 250) is turned off; wherein the switching unit (160, 250) and the voltage distribution unit (170, 260) are connected to a communication terminal assembly (CT1, CT2), and the communication terminal assembly (CT1, CT2) is connected to the communication unit (150, 240) through the switching unit (160, 250) and the voltage distribution unit (170, 260), wherein the communication terminal assembly (CT1, CT2) is connected to the communication lines (CL1, CL2) to receive a signal a voltage adjustment unit (190, 280) provided between the communication unit (150, 240) and the communication terminal assembly (CT1, CT2), the voltage adjustment unit being configured to prevent burning of the communication unit (150, 240) due to line connection errors by being configured to adjust the voltage applied to the communication unit (150, 240) and transmit the adjusted voltage to the communication unit (150, 240), such that when voltage exceeding a designated voltage is applied to the voltage adjustment unit (190, 280) through the power lines (PL1, PL2) connected by error to the first communication unit (150, 240), the voltage adjustment unit (190, 280) adjusts the applied voltage to the designated voltage or less; and a control unit (130, 220) configured to turn the switching unit (160, 250) off when the at least one of the indoor unit and the outdoor unit enters a standby mode, and turn the switching unit (160, 250) on based on the voltage distributed by the voltage distribution unit in the standby mode.