Security system with serial number coding and methods therefor

#This invention relates to security systems, and in particular to a system and method for using a masking algorithm as an operator on a security system device serial number to ensure that the device is compliant with the system.

#Random or sequential serial numbers have been used to set up unique identification codes for various radio controlled appliances such as garage door openers, and security systems devices such as intrusion detectors, smoke alarms, PIR sensors, etc. These identification codes are embedded in each security system device and registered or “learned” at the time of their installation by the control panel that operates the security system. Once registered with the control panel, the device will be able to communicate with the control panel as required (e.g. send and receive status messages, etc.) A device that has not been properly registered will be unable to communicate with the control panel.

#It may be desirable for a security system to register security devices manufactured at a certain location, but not from others, even if the serialization and other communications protocols would otherwise render the device registrable. As such, the present invention relates to the use of an encoding algorithm utilizing the existing serial number formats to allow or disallow registration of particular security devices, depending on the implementation of the algorithm.

#FIG. 1A is a block diagram of the system of the present invention;

#FIG. 2 is detailed block diagram illustrating the encoding of the serial number in conjunction with the masking algorithm;

#FIG. 3 is a table illustrating the functionality of an example masking algorithm;

#The preferred embodiment of the present invention will now be described with respect to the Figures. A security system device 8, such as a PIR sensor, intrusion detector, smoke alarm or the like, is programmed with a unique serial number or identification number sometime during the manufacturing process. A serial number generation function 6 operates in conjunction with a mask generation algorithm 4 to utilize only certain serial numbers from the pool of available serial numbers; i.e. only those that meet or comply with the masking algorithm. After the device 8 is distributed to a system installer, it is physically connected to a control panel 12 (either by wired bus 14 or a wireless connection such as an RF link) and a registration or learning process is undertaken by the control panel. During this process, the control panel will store the serial number of the device 8 so that it can communicate with it during normal operation, as well known in the art. In accordance with this invention, a mask reading algorithm 10 is applied to ensure that the control panel will learn only the serial numbers of the compliant devices 8.

#FIG. 2 illustrates an exemplary embodiment of the serial number generation and masking of the present invention, and FIG. 5 is a flowchart of the methodology employed. In this embodiment, serial numbers are generated sequentially by using a counter function 20, which simply cycles through a given pool of serial numbers as required. A 16-bit serial number 20 is generated that can range from 0000000000000000 to 1111111111111111. Of course, any size serial number may be used, and a 16-bit number is shown here for illustration purposes only. In addition, other types of serial number generation methods may be used, such as a random or pseudo-random number generator.

#An exclusive-OR gate 24 operates on two of the available bits, which may be arbitrarily chosen. In this example, Bit 1 and Bit 4 are used, but any combination will work within the spirit and scope of this invention. Moreover, any number of inputs may be used, bearing in mind that the number of bits operated on will affect the amount of available serial numbers as will become apparent below.