| 摘要 |
The present invention relates to a device for surveillance and for anti-theft protection. A surveillance device comprises beacons (18) which include means for short-range transmission of a first coded radio signal which are activated by a sensor for detection of the movement of the object carrying the beacon, and comprises transmitters (19) which include means for medium-range transmission of a second coded radio signal in response to the reception of the first signal, and, preferably, it includes at least one receiver (20) which can receive and decode the said second coded radio signal and display, on synoptic visual display means, the position of the beacons detected by the transmitters. The technical field of the invention is that of signalling and of signal transmission. <IMAGE>
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