Patent ID: 6950008

Claim:
Method for the authentication of a first transceiver unit with respect to a second transceiver unit, located at a distance, comprising: by means of the first unit a first signal is transmitted via an aerial, connected to it; when the second unit is within the reception range of the first unit, the first signal is received by means of the second unit via an aerial connected to it, and on the basis of the first signal received, a value is measured that characterizes the electro-magnetic field strength generated by the first signal at the location of the second unit, and a second signal is transmitted via the aerial connected to the second unit, which contains the information of the value characterizing the field strength; the second signal is received by the first unit via the aerial connected to the first unit, and on the basis of the second signal received, a value is measured that characterizes the electro-magnetic field strength generated by the second signal at the location of the first unit, where the values characterizing the field strengths generated by the transmission of both the first and the second signals are compared in order to determine whether the two field strength equivalent values corresponding to the coupling between the two aerials do, in fact, coincide, whereby a release signal is generated only when coincidence is determined.