Fecha de publicación: 03/08/2022 Fuente: Wipo "IOT" An embodiment of the present invention may comprise: a communication terminal for requesting, from an IoT switchgear via sound wave communication, one or more operations among manager registration, user registration, transmission of a changed password, transmission of a one-time digital key for a user, which is for the user himself/herself to open or close the IoT switchgear, and transmission of a one-time digital key for another person, which is for a terminal of another user to open or close the IoT switchgear; and the IoT switchgear for performing manager registration, user registration, a change of a password, storage of a one-time digital key for a user, and opening or closing of a door by using a one-time digital key for another person, which are requested by the communication terminal via sound wave communication with the communication terminal.