Data transmission method and single-networkcable extender for HDMI (High Definition Multimedia Interface) signals

The invention provides a data transmission method and a single-network cable extender for HDMI (High Definition Multimedia Interface) signals. The data transmission method comprises the steps of receiving the HDMI signals; loading four pairs of differential signals in the HDMI signals to four pairs of twisted pairs of a single-network cable in an alternating current coupling mode; and loading an SDA signal and an SCL signal in DDC signals to any two pairs of differential signals through magnetic beads in a direct current coupling mode, thereby transmitting the HDMI signals through the single-network cable. According to the method and the extender, in a data transmission process, the TMDS signal transmitted on the network cable is the encrypted TMDS signal in the HDMI signals, so the data is protected in the data transmission process, and the problem that data content is copied is avoided. The single-network cable extender for the HDMI signal is used for realizing the transmission method.