Abstract: The presence/absence of an image information request signal HSYNC output from each of a plurality of display devices is monitored. Based on the monitoring result, image information stored in an image memory of a display controller incorporated in a host computer is distributed to each display device.

Abstract: Signals are transmitted through a plurality of transmission channels, each including at least a pair of signal lines for transmitting an interface signal, between a transmitter and a receiver. A predetermined signal is modulated by a modulator with a high-frequency signal, and the modulated signal is provided to a signal line of one of the plurality of transmission channels. A demodulator receives the modulated signal transmitted via this signal line, and demodulates the modulated signal from the signal line based on the frequency of the high-frequency signal. According to the above-described configuration, an interface control method and apparatus which can newly exchange other data and control signals while conforming to existent interface specifications are provided.

Abstract: The tuner unit of a digital broadcast receiving apparatus receives a digital broadcast and generates a data stream from a digital broadcast signal having a desired modulation frequency. A data stream of a digital broadcast is also input from an external digital broadcast receiving apparatus via an external I/F. A stream switching unit and demultiplexer play back the content on a desired channel, contained in the two data streams, on an image display unit in real time, and at the same time, store the content on the other channel, contained in the other data stream, in a storage unit. This makes it possible to watch one of at least two programs with different modulation frequencies while recording the other program.