摘要 |
The present invention uniquely applies data communications network techniques to a security system. A series of slave transponders are coupled via a full duplex bus to a master node. The master node is coupled to other master nodes to form a network. The master node periodically polls its slave transponders to authenticate them. Each transponder has processing capability to give a distributed processing system. Each master node is a gateway which directs transmissions to the appropriate end point. The system uses an accordion-like protocol which can have fields added or deleted in a specific structure to conform the protocol to the particular message being transmitted. The protocol begins with address bytes identifying the destination followed by a control field which identifies the fields which are present. For a broadcast, rather than a point-to-point transmission, a process ID field in the protocol determines what area or function has to be addressed in all units. This area or function can be addressed for a large number of nodes by using this protocol field. The protocol is data transparent, it will handle any type of data. A sequence field allows the protocol to simultaneously handle redundant and non-redundant lines. The protocol allows point-to-point encryption of data and can operate over any media, electrical, optical, RF, etc. The routing algorithm includes an authentication byte attached by a particular transponder node and authenticated by a bus master connected to that node. The bus master substitutes its own authentication byte and sends the transmission along to the next point, where the authentication process is repeated. This allows authentication without requiring decrypting and re-encrypting of the transmission at each intermediate point.
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