Interface control system for exchanging signals by superposing signals to an existed signal line using low voltage differential signal

An interface control method comprising:

• transmitting a first signal comprising an interface signal using low voltage differential signaling over one of a plurality of transmission lines, each including at least a pair of signal lines, the first signal being transmitted from a transmission end to a reception end using both signal lines of said pair of signal lines;
• modulating a second signal with a high-frequency signal, to produce a modulated signal;
• providing the modulated signal to a single signal line of said pair of signal lines, the modulated signal being provided to the single signal line in a direction from the reception end toward the transmission end;
• and
• extracting the modulated signal from the single signal line, and demodulating the extracted signal.

An interface control apparatus comprising:

• a plurality of transmission channels each including at least a pair of signal lines for transmitting an interface signal;
• a transmitter circuit, arranged to transmit a first signal using low voltage differential signaling via both signal lines of a pair of signal lines of said plurality of transmission channels;
• a receiver circuit, arranged to receive the first signal transmitted via said pair of signal lines of said plurality of transmission channels;
• a modulator, arranged to modulate a second signal with a high-frequency signal and to provide the modulated signal to a single signal line of said pair of signal lines;
• and
• a demodulator, arranged to extract the modulated signal from that single signal line, and to demodulate the extracted signal.