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Appliance control

  • US 4,200,862 A
  • Filed: 12/28/1977
  • Issued: 04/29/1980
  • Est. Priority Date: 01/07/1977
  • Status: Expired due to Term
First Claim
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1. An electrical appliance control system for controlling electrical appliances within a building and comprising:

  • (a) a power main of the building;

    (b) a plurality of power outlets of the main;

    (c) a transmitter unit having;

    (1) input means for entering any one of a plurality of addresses into the transmitter unit;

    (2) means for generating, synchronously with the mains voltage, a multibit digital signal, comprising a multibit digital address signal representing an entered address, the digital signal being modulated on a carrier the frequency of which is a plurality of times greater than mains frequency, so that the bits of the digital signal comprise predetermined numbers of cycles of the carrier, the predetermined numbers depending upon the bit values, and a period within each bit occurring near a zero crossing point of the mains voltage; and

    (3) output means for coupling the modulated digital signal onto the main; and

    (d) at least one slave unit for controlling the supply of power to appliances and having;

    (1) means for defining an address for that slave unit;

    (2) a power input coupled to the main within the building;

    (3) means for receiving from said power input said digital signal;

    (4) means for recognizing the logical values of the bits of the received digital signal by counting during said period the number of cycles of the carrier and determining the value of the bit in dependence upon which of two non-overlapping number ranges contains the counted number; and

    (5) means for comparing the digital address signal received by the receiving means with the address of the defining means and for rendering the slave unit operable to effect an appliance power supply control operation when correspondence is found between said address and the digital address signal;

    (e) at least one of the transmitter and slave unit being releasably coupled to a power outlet of the main so as to be usable optionally at various placed within the building.

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