Burglar alarm system having reduced wiring

• US 20040155769A1
• Filed: 12/30/2003
• Published: 08/12/2004
• Est. Priority Date: 01/03/2003
• Status: Active Grant

• Current Assignee: New Day Investment Limited
• Original Assignee: Leeds Electronic Engineering, Ltd.
• Inventors: Lee, John Kam Ho
• Granted Patent: US 6,992,579 B2
• Time in Patent Office: Days
• US Class Current: 340/506
• CPC Class Codes: G08B 25/06 using power transmission lines
• CPC Class Codes: G08B 29/06 Monitoring of the line circuits, e.g. signalling of line faults

Abstract

Normal hard-wired domestic burglar alarms have cables with six conductors extending between the alarm controller and each remote input/output device (such as an entry keypad). The present alarm system has an alarm controller, a remote input/output device, a cable extending from the alarm controller to the remote input/output device, the cable comprising two conductors only, providing power to the remote input/output device. A signal processor at the controller monitors and processes voltage and current in the conductors to affect functions of the alarm system. A mixer at the remote input/output device processes voltage and current in the conductors to affect functions of the alarm system.

Claims

1. An alarm system comprising:

an alarm controller,

a remote input/output device,

a cable extending from the alarm controller to the remote input/output device, the cable comprising two conductors providing power to the remote input/output device, and

a signal processor at the controller monitoring and processing voltage and current fluctuations in the conductors and controlling functions of the alarm system.

2. The alarm system of claim 1 further comprising a mixer at the remote input/output device operative to affect current and voltage at the two conductors.

3. The alarm system of claim 1 wherein the signal processor monitors for predefined voltage and current levels at the two conductors.

4. The alarm system of claim 2 wherein the mixer applies predefined voltage and current levels at the two conductors.