×

Emergency alert system

  • US 5,029,290 A
  • Filed: 02/02/1990
  • Issued: 07/02/1991
  • Est. Priority Date: 02/02/1990
  • Status: Expired due to Fees
First Claim
Patent Images

1. An alarm system suitable for use in a telecommunications network which includes central means for selectively coupling respective communications signals of a predetermined polarity to a plurality of remote stations, each of said remote stations having an electrical conduction path to said telecommunications network for receiving one of said communications signals, said alarm system comprising:

  • alarm request means for generating an alarm request signal to notify selected ones of the plurality of remote stations of an alarm condition;

    alarm signalling means, coupled to said telecommunications network and responsive to said alarm request signal, for applying an alarm signal to the respective electrical conduction paths of said selected remote stations in place of any of said communications signals, said alarm signal having a polarity which is reversed with respect to the polarity of the communications signals;

    alarm indication means, coupled to at least the selected remote stations, and responsive to the alarm signal for indicating the alarm condition and being substantially unresponsive to the communications signals having said predetermined polarity.

View all claims
  • 7 Assignments
Timeline View
Assignment View
    ×
    ×