A master device transmits received image data to a mobile phone terminal and includes a storage unit that stores sensor setting information including at least sensitivity or a threshold value of a sensor, the mobile phone terminal includes a display and input unit, displays the image data transmitted from the master device on the display and input unit, requests the master device to provide the sensor setting information when receiving a predetermined operation, displays the sensor setting information transmitted from the master device on the display and input unit, and transmits the changed sensor setting information to the master device when receiving an operation of changing the sensor setting information, and the master device updates the sensor setting information stored in the storage unit using the sensor setting information after changing transmitted from the mobile phone terminal.