Whether or not HDCP authentication is necessary is determined and managed for each device connected to an HDMI port. In selector control, when switching to an HDMI port to which is connected a video signal output apparatus that requires HDCP authentication, DDC access is turned off by setting an HPD signal to Low. Communication is then resumed after a predetermined amount of time has passed by setting the HPD signal to High and thereby turning the DDC access back on. When switching to an HDMI port to which is connected a video signal output apparatus that does not require HDCP authentication, the HPD signal is kept at High, and video and audio data is output without resuming the DDC access.