MONITORING DEVICE, CARRIER DEVICE AND METHOD INVOLVING A MONITORING DEVICE AND A CARRIER DEVICE

摘要

A method for monitoring the presence of a monitored item comprising the steps of - Transmitting a poll signal from a monitoring device arranged in a mobile telephone or similar, to a carrier device arranged on the monitored item, said poll signal having predetermined characteristics identifying the monitoring device and the carrier device, - transmitting a response signal from the carrier device to the monitoring device in response to said poll signal said response signal enabling the monitoring device to identify and determine the position of the carrier device - taking action if it is determined that the distance between the monitoring device and the carrier device is greater than a predetermined threshold distance. Theft or loss of valuable items can be detected if they are provided with carrier devices according to the invention.