ALARM DETECTION SYSTEM

• US 3,611,363 A
• Filed: 01/15/1970
• Issued: 10/05/1971
• Est. Priority Date: 01/15/1970
• Status: Expired due to Term

• Current Assignee: Alan F. Mccrea, Hugh V. Snively
• Original Assignee: Alan F. Mccrea, Hugh V. Snively
• Inventors: McCrea, Alan F., Snively, Hugh V.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Mooney, Robert J.
• Application Number:
  US05/003,085
• Time in Patent Office: 628 Days
• Field of Search: 340/412,413,415,213,213.1,147R,182,184 325/53,54 179/2R,5R
• US Class Current: 340/518
• CPC Class Codes: G08B 26/002 only replying the state of the sensor

Abstract

An alarm detection system including a plurality of remote stations, each of the remote stations having a group of field points and an alarm signal generator responsive to an alarm condition at the field points to generate an alarm signal, a telephone line for each of the remote stations, and a central control station communicating with the remote stations through the telephone lines and having a plurality of alarm receivers connected with each telephone line, respectively, to receive alarm signals and initiate a scan of the field points at remote stations generating alarm signals.

Claims

1. An alarm detection system comprising a plurality of remote stations, each of said remote stations including a group of field points, and alarm-signal-generating means connected with said group of field points to generate an alarm signal in response to the existence of an alarm condition at any of said field points;

a plurality of communication means coupled with said plurality of remote stations; and

a central control station including address-generating means for generating address signals corresponding to individual field points at said remote stations, a plurality of receiving means coupled with said plurality of communication means to receive said alarm signals and having output means connected with said address-generating means, and control means coupled with said address-generating means and said plurality of communication means for selectively controlling communication between said remote stations and said central control station whereby said control means is reSponsive to an alarm signal from one of said remote stations to establish communication between said one remote station and said central control station to permit scanning of said group of field points at said one remote station by said address signals.

2. The invention as recited in claim 1 wherein said control means includes input means for receiving said alarm signals from each of said alarm-signal-receiving means separately, scanning means for interrogating said input means to determine which of said remote stations generated said alarm signals, and switch means connected with said plurality of communication means and responsive to said scanning means to selectively establish communication with said remote stations

3. The invention as recited in claim 2 wherein said input means includes storage means for each of said receiving means, and said scanning means includes counting means for sequentially providing pulses to said storage means corresponding to the number of said remote stations included in said alarm detection system.

4. The invention as recited in claim 3 wherein said plurality of communication means includes a plurality of telephone lines, and said switch means includes a pair of contacts connecting each of said telephone lines with said address-signal-generating means.

5. The invention as recited in claim 1 wherein said alarm-signal -generating means means generates high-priority alarm signals and low-priority alarm signals in response to high-priority and low-priority alarm conditions existing at said field points, respectively, and said control means includes priority means for establishing communication with said remote stations generating said high-priority alarm signals before establishing communication with said remote stations generating said low-priority alarm signals.

6. The invention as recited in claim 5 wherein said control means includes input means for receiving said high-priority and low-priority alarm signals from each of said receiving means separately scanning means for interrogating said input means to determine which of said remote stations generated said high-priority and low-priority alarm signals, and switch means connnected with said plurality of communication means and responsive to said scanning means and said priority means to selectively establish communication with said remote stations.

7. The invention as recited in claim 6 wherein said input means includes storage means for each of said high-priority and low-priority alarm signals from each of said receiving means, and said scanning means includes counting means for sequentially providing pulses to said storage means corresponding to the number of said remote stations included in said alarm detection system.

8. The invention as recited in claim 5 wherein said alarm-signal-generating means includes first means responsive to high-priority alarm conditions existing at said field points to provide a high-priority pulse, and second means responsive to low-priority alarm conditions existing at said field points to provide a low-priority pulse.

9. The invention as recited in claim 8 wherein said alarm-signal-generating means includes a transmitter connected with said first means and said second means and providing a first frequency signal in response to said high-priority pulse and a second frequency signal in response to said low-priority pulse.

10. The invention as recited in claim 9 wherein said first means includes a first monostable multivibrator, said second means includes a second monostable multivibrator, and the duration of said low-priority pulse is greater than the duration of said high-priority pulse.

11. The invention as recited in claim 10 wherein said alarm-signal-generating means includes means responsive to operation of said first means to inhibit the operation of said second means.

12. The invention as recited in claim 5 wherein said control means includes a first plurality of memory flip-flops receiving said high-priority alarm signals from each of said receiving means, a second plurality of memory flip-flops receiving said low-priority alarm signals from each of said receiving means, a first active level flip-flop receiving the outputs from said first plurality of memory flip-flops, and a second active level flip-flop receiving the outputs from said second plurality of memory flip-flops, said first and second active level flip-flops having outputs connected with said address-generating means.