Abstract: A parking system includes a portable parking tag for each vehicle and a reading device. The portable parking tag includes a non-contact data communications circuit for effecting data transfer by mutual electromagnetic coupling with the reading device, a memory coupled to the data communications circuit for storing at least one parking parameter, and an antenna coupled to the data communications circuit for transmitting a first signal representative of each parking parameter. The reading device includes an antenna for receiving a first signal, a reading circuit coupled to the antenna and responsive to the first signal for reading each parking parameter stored in the parking tag memory, a validity verification circuit coupled to the reading circuit and responsive to the first signal for generating a validity signal, and output circuit coupled to the validity verification circuit and responsive to the validity signal for producing a visual or audible output signal.

Abstract: A data transmission system for the non-contact transmission of data between a station and a portable data carrier. The station includes a station transmitter operating at a predetermined frequency for generating a first signal and a demodulator for detecting a second signal superimposed on the first signal. An antenna is coupled via a length of cable to the station transmitter via a matching circuit so as to be operative at said frequency regardless of the length of the cable. The portable data carrier includes supply means for coupling to a source of electric power and a data carrier tuned antenna circuit inductively coupled with the station transmitter so as to receive power from the station. A data carrier data modulator is provided for modulating the first signal with the second signal in response to data stored within the data carrier and, by means of said inductive coupling, enabling the data to be transmitted from the data carrier to the station.