An electronic device comprising: an HDMI connector unit having a plurality of pins with a first number of pins being used of said plurality of pins when an external device which operates using a first digital interface conforming to an HDMI, high definition multimedia interface, standard having three TMDS, transition-minimized differential signaling, channels and a TMDS clock channel is connected to said connector unit, and a second number of pins which are less than said first number of pins being used of said plurality of pins when an external device which operates using a second digital interface conforming to an HDMI standard having one TMDS channel and no additional TMDS channels and no clock channel is connected, and further comprising: a digital interface determining unit configured to determine whether the digital interface of an external device connected to said connector unit is said first digital interface or said second digital interface, based on the voltage state of a predetermined pair of pins to which a differential signal associated with one of said TMDS channels is input when an external device which operates using said first digital interface is connected and to which no differential signal is input when an external device which operates using said second digital interface is connected to said connector unit; and a control unit configured to perform switching control so that a data transmission unit connected to said connector unit operates using a digital interface determined by said digital interface determining unit. an HDMI connector unit having a plurality of pins with a first number of pins being used of said plurality of pins when an external device which operates using a first digital interface conforming to an HDMI, high definition multimedia interface, standard having three TMDS, transition-minimized differential signaling, channels and a TMDS clock channel is connected to said connector unit, and a second number of pins which are less than said first number of pins being used of said plurality of pins when an external device which operates using a second digital interface conforming to an HDMI standard having one TMDS channel and no additional TMDS channels and no clock channel is connected, and further comprising: a digital interface determining unit configured to determine whether the digital interface of an external device connected to said connector unit is said first digital interface or said second digital interface, based on the voltage state of a predetermined pair of pins to which a differential signal associated with one of said TMDS channels is input when an external device which operates using said first digital interface is connected and to which no differential signal is input when an external device which operates using said second digital interface is connected to said connector unit; and a control unit configured to perform switching control so that a data transmission unit connected to said connector unit operates using a digital interface determined by said digital interface determining unit. a digital interface determining unit configured to determine whether the digital interface of an external device connected to said connector unit is said first digital interface or said second digital interface, based on the voltage state of a predetermined pair of pins to which a differential signal associated with one of said TMDS channels is input when an external device which operates using said first digital interface is connected and to which no differential signal is input when an external device which operates using said second digital interface is connected to said connector unit; and a control unit configured to perform switching control so that a data transmission unit connected to said connector unit operates using a digital interface determined by said digital interface determining unit.