ALARM SIGNALLING METHOD BASED ON MONITORING PROXIMITY OF RECEIVING AND TRANSMITTING RADIO DEVICES Russian patent published in 2012 - IPC G08B1/08 G08B21/24 

FIELD: physics, signalling.

SUBSTANCE: method is intended to alert the owner of protected items to the removal of said items from a given proximity zone and is carried out with the aid of a transmitting and receiving device carried by the owner and transmitting and receiving devices attached to the protected items. The alarm signalling is implemented in that the telephone periodically transmits, via communication channels established by Bluetooth devices of the telephone and tags, alarm signalling codes that are unique to each tag and are in the form of series of interrogation radio alarm signals with set series repetition intervals for each tag and radio alarm signal repetition intervals within a series. The telephone activates warning signals identifying a tag with an activated warning upon expiry of set time periods for the transmission and return reception by the telephone of the encoded radio alarm signals, said periods being counted from the times when the telephone sends the first radio alarm signals in the series if, during these periods, the telephone does not receive at least one return radio signal with an unimpaired alarm signalling code from each of the tags.

EFFECT: high noise-immunity.

7 cl, 2 dwg