A data communication restricted content providing device executes a program of game content, accepts operation input for the game content, controls the game content in accordance with operation input, generates, based on information of a changed progress condition of the game content, audio data indicating the progress condition, and plays back the audio data. An information processing device acquires an audio signal played back by the content providing device, extracts information of the progress condition from the audio signal, and outputs, to an external device, information of the progress condition.