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Door ajar signalling device

  • US 5,289,534 A
  • Filed: 11/21/1991
  • Issued: 02/22/1994
  • Est. Priority Date: 11/21/1991
  • Status: Expired due to Fees
First Claim
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1. A system for alerting a user when a predetermined condition exists, comprising:

  • a host telephone having an on/off-hook indicator and an alert device;

    a controller coupled to the host telephone;

    an indicator circuit providing an indicator signal to the controller when the predetermined condition exists;

    means for timing a preset time duration when the predetermined condition exists, said timing means providing a time-out signal when the preset time duration elapses;

    means for operating the controller to signal the host telephone when the time-out signal is provided in order to activate the alert device for a first preset alert duration;

    means for providing a warning signal to the host telephone when the on/off indicator indicates an off-hook condition of the host telephone; and

    means for stopping the warning signal via a stop signal input to the controller through the host telephone;

    wherein an on-hook signal from the on/off-hook indicator also operates the means for stopping the warning signal; and

    wherein the indicator circuit is a door ajar indicator switch and the predetermined condition is a door ajar condition.

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