Patent attributes
A data output apparatus receives a first command from a first device, and receives a second command from a second device. The apparatus (a) sets an output terminal to a locked state where a data format thereof is locked to a data format indicated by the first command and where the terminal cannot output video data whose data format is different, if the first command is received while the terminal is being set to an unlocked state, (b) determines whether a data format indicated by the second command is the same as the data format of the terminal, if the second command is received while the terminal is being set to the locked state, and (c) transmits a response for informing the second device that the second command is accepted, if the data format indicated by the second command is the same as the data format of the terminal.