An interface device includes an electronic device and an input device for communicating with the electronic device. The electronic device includes a display layer, a sensor layer, and a controller for outputting a first uplink signal and a second uplink signal to the sensor layer. The input device includes a communication unit for receiving an uplink signal from the sensor layer, a memory for storing first information and second information, a signal determination unit for determining whether the uplink signal is the first uplink signal or the second uplink signal, based on the first information and the second information, and a signal conversion unit for outputting conversion data in response to the uplink signal being the second uplink signal.