the communication module 200 to determine whether the operation voltage is normally supplied to the communication module 200 as a result of the determination if it is determined that the operation voltage has been supplied to the power terminal of the communication module 200 the operation determination unit 312 determines that the communication module 200 operates normally if it is determined that the operation voltage has not been supplied to the power terminal of the communication module 200 the operation determination unit 312 determines that the communication module 200 does not operate normally as a result of the determination if it is determined that the communication module 200 operates normally the switching controller 314 may connect the movable terminals of the plurality of switching elements 314 1 314 2 314 3 314 4 to the fixation terminal a of one side in response to the control of the operation determination unit 312 then the predetermined data received by the reception terminal rx 1 of the first i o port 202 may be inputted into and processed by the communication module 200 via the switching element 314 1 and the inputted data may be amplified by the communication module 200 and outputted to the transmission terminal tx 2 of the second i o port 204 via.