Patent ID: 7319844

Claim:
Identification system comprising a plurality of devices able to be addressed radio frequency by a reading unit comprising a reading antenna, each device comprising a processing circuit connected to a first antenna, designed to be coupled to an external antenna, energy recovery means and a second antenna designed to be coupled to an antenna of at least one higher-ranking device, the processing circuit comprising means for applying radio frequency signals to the terminals of the second antenna, each device having a predetermined ranking, the external antenna to which the first antenna of the rank one device is coupled being the reading antenna and at least two devices of adjacent rankings being arranged in such a way as to establish an electromagnetic coupling between the first antenna of a device of ranking higher than one and the second antenna of the lower-ranking device, system wherein a device of specific ranking is associated with a sub-set of higher-ranking devices so as to form a hierarchical tree structure, wherein addressing by the reading unit of a device ranking higher than one is performed by means of the associated lower-ranking devices, wherein, each device having a unique identification code, the reading unit transmits identification request signals, each device transmits a signal representative of its identification code when it receives an identification request signal, the reading unit transmits transparent mode activation signals selectively intended for at least one previously identified device, the device in transparent mode transmitting the signals received on its first antenna to its second antenna and retransmitting the signals it receives on its second antenna to its first antenna.