Electromagnetic transponder e.g. dual integrated circuit card, for contactless exchanging of protected data with reader for bank card, has electric circuit switched from one state to another state when resonant circuit is powered by reader

摘要

The transponder (1) has a resonant circuit (2) provided with an antenna and a capacitor. A light detection unit detects exposure of the transponder in a light to modify an electric circuit of the transponder, where the light detection unit is designed as a photodiode (23). The electric circuit is switched from one state in which the circuit does not allow a reader for reading and writing in a memory unit (5), into another state in which the circuit allows the reader to read and write in the memory unit when the resonant circuit is contactlessly powered by the reader. An independent claim is also included for a method for providing contactless communication between a reader and a transponder.