| 摘要 |
An alarm system is designed with at least one local alarm loop 2, to which one or more alarm stations 3, 3', 3" are connected. The particular alarm station is connected via the alarm loop to a central unit 1, which sends polling signals and receives response signals from the alarm station regarding the condition of its data transmitter G, whereupon an indication is also obtained automatically as the condition of the alarm loop and the system equipment. Said polling and response signals are sent in encoded form, making use of a first and second encoding element S, C in the central unit and at the alarm station, respectively. The generating of the code in the system is designed to occur randomly by means of a random generator S included in the central unit 1, so that the code used in the system remains unknown to the outside, even to an operator. <IMAGE> |
