| 摘要 |
Device in an alarm system, notably a security alarm system, that includes a programmable transmitter (1) with an automatic dialling function via connections in a telephone system (V1, V2) to one or more alarm receivers. The transmitter can be programmed with the number shared with the alarm receiver as well as its own number, such as an alarm code number, to allow identification at the respective alarm receiver (2) upon signal from the transmitter. The transmitter includes or is connected to one or more memory units (4), in which said numbers are stored. Additional memory for the program from which the alarm system works in included in the equipment. It is essential that the transmitter program and/or stored information be intact so that correct alarm system functioning is maintained. With this invention, a control unit (5) is used to continuously or periodically check that no change has been made to the stored information. The check can consist of a simple sum control or of some other more sophisticated means. When a change occurs or has occurred a local alarm signal is released or transferred via a secondary transmitter to the alarm receiver via a fixed or dialled connection in the telephone system.<IMAGE> |
