To provide a
communication device capable of determining that an unauthorized device is connected by the
communication device as a single unit.SOLUTION: A
communication device includes a
transceiver 10 and a controller 20. The controller outputs a transmission
signal including identification information as a communication
signal to be transmitted through a communication wire, and receives a reception
signal including the identification information as a communication signal received through the communication wire. The
transceiver is connected to the communication wire, transmits the transmission signal inputted from the controller from the communication wire, and outputs the reception signal received from the communication wire to the controller. The
transceiver includes a storage part 132 for storing the identification information included in the transmission signal, and a
processing part 131 for determining that an unauthorized device is connected to the communication wire in the case that the same identification information as the identification information included in the reception signal is stored in the storage part.SELECTED DRAWING: Figure 2