Abstract: System for interchanging data between at least two contactless data storage media, particularly contactless chip cards, wherein at least one of the contactless data storage media controls the data interchange as a master, and the at least one other data storage medium is controlled as a slave.

Abstract: The invention relates to a method for transmitting data in a system comprising a reader that creates an interrogation field which contains at least two transponders that, after a start signal has been given in the interrogation field, transmit through load modulation of the interrogation field a uniquely assigned bit sequence back to the reader.

Abstract: The invention relates to a method for calibrating an oscillating receiver circuit of a transponder in an RFID system to resonance to the frequency of an inquiry signal transmitted by a reader, the oscillating receiver circuit comprising at least one inductive resistor and at least one capacitor. Immediately after the start of reception of the inquiry signal, capacitors are connected in increments to the capacitance of the oscillating receiver circuit until such time as the rectified, smoothed inquiry signal assumes a maximum voltage value. This active self-calibration is performed upon each initialization of the transponder but can also be addressed by having the reader send a special sequence to the transponder.