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Centralized monitoring method for security system

  • US 4,740,787 A
  • Filed: 09/25/1985
  • Issued: 04/26/1988
  • Est. Priority Date: 01/25/1985
  • Status: Expired due to Fees
First Claim
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1. A centralized monitoring method for a security system having a plurality of terminal units connected in parallel to common lines coupled to a central unit, said terminal units transmitting their individual data in a predetermined calling sequence in response to a sequential calling operation carried out through said common lines by said central unit, said central unit detecting abnormal conditions such as fires and gas leakage in response to said individual data, said method comprising the steps of:

  • providing special ones of said plurality of terminal units with means for generating special priority data having a priority over said individual data of each of said plurality of terminal units and for transmitting said special priority data to said central unit independently of said sequential calling operation, said means for generating special priority data comprising a transmitter including a contact means;

    entering addresses of said special ones of said plurality of terminal units into said central unit;

    employing said contact means to enable an interrupt signal to be transmitted to said central unit;

    employing said contact means to enable a transmitter operation signal to be transmitted to said central unit;

    employing said central unit, responsive to receipt of said transmitter operation signal, to suspend said first sequential calling operation and to perform a second sequential calling operation only on said special ones of said plurality of terminal units in order to detect which one of said special ones of said plurality of terminal units transmitted said transmitter operation signal to said central unit; and

    employing said central unit, responsive to receipt of said interrupt signal and said special priority data from said special one of said special ones of said plurality of terminal units, to transmit a calling signal to said one of said special ones of said plurality of terminal units, said calling signal having priority over all other signals transmitted to or from all others of said plurality of terminal units.

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