A communication system includes a master device, a connector, a superordinate trunk cable connecting the master device and the connector, a superordinate slave device connected to the connector, a subordinate slave device, and a subordinate trunk cable connecting the connector and the subordinate slave device. The connector includes a superordinate power line via which power is supplied from the master device, a power branching unit to divide the superordinate power line into a first power line connected to the superordinate slave device and a second power line connected to the subordinate slave device, a superordinate signal line via which communication data between the master device and the superordinate slave device is configured to be transmitted, and a subordinate signal line via which communication data between the superordinate slave device and the subordinate slave device is configured to be transmitted.