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Add-on alert system

  • US 4,612,535 A
  • Filed: 11/01/1984
  • Issued: 09/16/1986
  • Est. Priority Date: 11/01/1984
  • Status: Expired due to Fees
First Claim
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1. In a signaling system of the type having at least one detector for monitoring a zone within a building and producing an audible signal when an emergency condition is sensed, an add-on apparatus for use in conjunction with the detector that includesan indoor unit located in the zone monitored by the detector and at least one outdoor unit located adjacent the monitored zone on the outside of the building,said indoor unit including a microphone mounted in close proximity with the detector for energizing a light emitting element of an optical isolator when the detector produces an audible signal, said optical isolator also having a light-sensitive element, means coupled to the light-sensitive element of the optical isolator for closing a contact when the optical isolator is energized and a radio transmitter connected to a power supply by the contact for providing a radio for broadcasting a radio frequency signal when the contact is closed, andsaid at least one outdoor unit including a radio receiver for receiving said radio frequency signal from the transmitter and applying an enabling potential from a power supply to an alarm circuit whereby an alarm is energized and a holding circuit for maintaining the alarm energized once the alarm circuit is enabled whereby the alarm persists after the transmitter stops broadcasting.

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