| 摘要 |
A security system using remote sensing units (1a-1d) and a transponder (18, 22) in either one-way or two-way radio communication with a central station (34). The invention provides for the continuous monitoring of remote points (200a-200d) in a particular area from a central station without need of physical connections between the central station and the remote points. The invention further comprises the added feature of using redundant code comparison to ensure the validity of the transmitted signal. |
