Radio controlled alarm system with substations and safe data transmission

Claim 1

Radio-controlled danger-signalling system, in particular fire-signalling, intrusion-signalling, emergency-call, paging or alarm signal, comprising at least one signalling unit, one centre and at least one substation that is disposed in such a way that it receives a signal broadcast by the signalling unit and passes it to the centre or to another substation, characterized in that a bidirectional radio link exists between the centre and/or the substations and/or the signalling units, the centre has a synchronization module that coordinates the bidirectional radio communication between the signalling units, the substations and/or the centre, each substation has a scanner that continuously scans the frequency bands or radio channels available for the radio link, the substation establishes a table containing the current receiving field strengths of the available frequency bands or radio channels on the basis of the scanning of the available frequency bands or radio channels, the substation determines the radio channels currently to be seized from said table, the substation transmits the table containing the current receiving field strengths of the available frequency bands or radio channels to the centre in a specified time cycle, the centre maintains these transmitted tables containing the current receiving field strengths of the available frequency bands or radio channels in the synchronization module, the synchronization module of the centre synchronizes the communication of the substations with one another, and the substations exchange with one another the radio channels preferably to be seized for the purpose of the radio link with one another from the respective tables containing the current receiving field strengths of the available frequency bands or radio channels.