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Intrusion detector system

  • US 4,166,273 A
  • Filed: 09/19/1977
  • Issued: 08/28/1979
  • Est. Priority Date: 09/19/1977
  • Status: Expired due to Term
First Claim
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1. An intrusion detector system comprising:

  • (a) means for transmitting an alarm signal,(b) means operative to receive the alarm signal and to provide an electric signal in response thereto,(c) means operative in response to the electric signal to provide a predetermined number of pulses having predetermined time periods,(d) a tone generator operative in response to the pulses for generating multiple tones of discreetly different frequencies during each pulse to provide a tone-coded message, each generator pulse having a combination of multiple tones of different frequencies than the combination of multiple tones of each other generator pulse,(e) means operative to transmit the tone-coded message,(f) the means for transmitting an alarm signal including;

    (1) a robbery transmitter that is directly activated to provide a first alarm signal, and(2) an intrusion transmitter for transmitting a signal into a zone under surveillance and receiving a signal from the zone to provide a second alarm signal in response thereto,(g) the means providing the timed pulses is activated by the second alarm signal, and(h) means receiving the timed pulses and activating the tone generator to provide a multiple tone combination during one timed pulse to indicate a burglary, and receiving the first alarm signal and activating the tone generator to provide a different multiple tone combination during the said one-timed pulse to indicate a robbery.

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