| 摘要 |
The invention concerns a system wherein the terminal comprises transmitter/receiver means (10, 12, 24, 26, 30, 38) with a communication coil (42) to radiate towards a first type of portable object an alternating magnetic field at a first modulated frequency, to receive a modulated disturbance produced in response, to radiate towards a second type of portable object an alternating magnetic field at a second modulated frequency, different from the first, and to receive a modulated disturbance produced in response. The first type of portable objects are essentially unequipped with their own power supply and derive their power supply from the magnetic field at the first frequency, whereas the second type of portable objects are essentially provided with their own power supply means not requiring remote power feeding.
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