METHOD FOR TRANSMITTING INTRUDER ALARM OPERATION MESSAGE Russian patent published in 2003 - IPC

FIELD: intruder alarms for vehicles and the like. SUBSTANCE: method that may be used, for example, for secret transmission of intruder alarm operation message in case of unauthorized access to vehicle involves step-by-step transmission of alarm signal from mobile unit transceiver mounted on guarded object to message addressee's transceiver with varying medium of signal transmission between devices as well as generation and transmission of encoded acknowledgement signal in reverse sequence to mobile unit transceiver on guarded object. In case of failure of acknowledgement signal transmission to mobile unit transceiver of guarded object within preset time of 1-2 s signal whose parameters correspond to message may be transmitted again, sound waves being used as primary signal transmission medium. In case of failure of acknowledgement signal arrival at transceiver mobile unit device of guarded object turns on acoustic alarm of guarded object within preset time of 1-3 s by means of mobile unit. EFFECT: enhanced reliability of informing guarded object owner about alarm operation in absence of special radio channel. 3 cl, 4 dwg