Various embodiments may include an identification device comprising: a data memory storing a piece of information containing an identification; a processor generating a signal indicating the piece of information; an optical-to-electrical energy converter supplying power for the processor and converting electromagnetic radiation from the surroundings into an electric current feeding the processor via a power connection; an output device with a data connection to the processor for transmitting the signal; and an executable program stored in the processor for reading an input signal transmitted via the power connection and superimposed on the electrical current.