초록 ▼

A security system for supervising the integrity of a communication line having a supervising apparatus which generates first and second random signals, compares these first and second randomly generated signals to provide a third signal and compares this third signal to a fourth signal, and a transp

A security system for supervising the integrity of a communication line having a supervising apparatus which generates first and second random signals, compares these first and second randomly generated signals to provide a third signal and compares this third signal to a fourth signal, and a transponder, also connected to the line, which compares the first and second randomly generated signals to provide the fourth signal to the communication line. The use of randomly generated signals increases the difficulty of breaching line security such that, when the supervisory apparatus detects a difference between the third and fourth signals, it can provide an appropriate alarm, indication, or control.

대표청구항 ▼

A communication system for communicating between a central processing unit and remote stations comprising: central processing means for transmitting remote station address messages; a communication line connected to said central processing unit for conveying said remote station address messages; dat

A communication system for communicating between a central processing unit and remote stations comprising: central processing means for transmitting remote station address messages; a communication line connected to said central processing unit for conveying said remote station address messages; data gathering apparatus means connected to said communication line for receiving said remote station address messages, said data gathering apparatus means including a plurality of remote stations, each station having module address means for storing a module address unique to said remote station, and remote station address means for storing a remote station address unique to said remote station, control logic means having sequencing means for sequentially supplying module addresses to said remote stations, each of said remote stations comprising module address comparator means connected to said module address means and to said control logic for supplying to said control logic the remote station address when there is a match between the module address stored in the remote station and the module address generated by said control logic means, remote station address comparator means for comparing the remote station address received from said central processing means to the remote station address of the selected remote station.