Security/prevention system with related device

Claim 1

A security/prevention system with related device, said device, said device being installed in a vehicle and comprising: a decoder; a microcomputer(3); a high-frequency(HF) part(10); a receiver modulator(4); an aerial part(8); and an aerial(8); said device operating with low-power transmission signals and obtaining the encoding and frequency of transmitted or received alarm signals by means of a roadside infrastructure, said roadside infrastructure comprising specific code and specific transmitters, thereby enabling said vehicle to receive at individual road sections, information on which frequency said device should receive or transmit alarm signals, and information on a digital code into which said alarm signals to be transmitted or received by said device are to be encoded, said device operating in a manner comprising the following features and steps: a) receiving said alarm signals comprising the steps of: 1a) selecting and checking the occupancy of a second random channel at a second frequency when a first receiving channel at a first frequency is occupied by an analog signal; 2a) receiving and processing said alarm signals when said first receiving channel is occupied by said alarm signals which have a valid code as defined by said roadside infrastructure; 3a) changing the receiving frequency of said HF part(10) by said receiver(70) or said microcomputer(3) after a certain first period of time that the alarm signals are received and processed, said first period of time being at least equal to the sum of transmission times of a transmission device on all receiving channels; 4a) selecting randomly by said microcomputer(3) a third channel at a third frequency, when said first receiving channel is free of signals for a certain second period of time, or, when after said certain second period of time, said decoder does not identify a specific code into which said alarm signals are encoded, or, when an analog signal appears on said receiving channel as a result of interference or use by another user; b) adding a weighting factor to individual digital information packages of alarm information included withing said alarm signal, said weighting factor defining a length of pause between said individual digital information packages; and c) transmitting said alarm signals comprising the steps of: 1c) selecting randomly by said microcomputer(3) one of a group of permitted frequencies corresponding to a selected channel; 2c) said microcomputer(3) sending said selected frequency by a first communication link(a) to said receiver(7) which checks the status of said selected frequency; 3c) said microcomputer(3) tuning, by said first communication link(a), said transmitter(6) to said selected frequency, when said selected frequency is unoccupied; 4c) said microcomputer(3) sending a certain number of digital information packages included within said alarm signals, by a second communication link(d), to said modulator(4); 5c) said modulator(4) sending said digital information packages, by a third communication link(e), to said transmitter(6); 6c) said transmitter(6) sending said digital information packages, by a fourth communication link(I), to said aerial part(8) or said aerial(9), which transmits said digital information packages; and 7c) commencing step 1c after a certain third period of time unless the transmission of said alarm signals is complete.