Portable data carrier medium i.e. smart card, has oscillating circuit whose detuning is caused by magnet read head when reading magnetic strip, where number of detuning of oscillating circuit is realized and processed by evaluation unit

摘要

The medium has a magnetic strip (2) with data that is selected by a magnet read head (101) of a reader (100). A coil (3) is arranged in the medium below the magnetic strip and formed in such a manner that detuning of an oscillating circuit (4) of the medium is detected. Detuning of the oscillating circuit is caused by a magnet read head when reading the magnetic strip. Number of detuning of the oscillating circuit detected by the coil is realized and processed by an evaluation unit in the reader or provided for processing by the reader. An independent claim is also included for a method for recognizing multiple selection of a magnetic strip of a portable data carrier medium.