| 摘要 |
Head end apparatus delivers video signals, e.g., premium and standard television programming to distinct locations such as hotel/motel rooms, an apartment or the like via a common MATV cable. The head end also transmits digital messages to receivers at each room location which are recovered via a phase detector and supplied to predetermined appropriate output utilization apparatus via a multiplexer and microprocessor. Similarly, messages generated at each room are transmitted upstream to the head end via the cable, employing a portion of the phase detector apparatus. In accordance with varying aspects of the present invention, the bilaterally propagating digital messages may comprise status controls for controlled equipment, e.g., electrical loads; and/or may comprise a data exchange for a communications application. Further, the room transmission apparatus is adapted to fail, if at all, in a noninterfering mode which does not comprise overall system operability.
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