A passive transponder has a power antenna which receives a power signal and a communication antenna which receives a communication signal. An information generating circuit creates a second communication signal in response to the first communication signal and outputs the second communication signal through the communication antenna. The information generating circuit is powered by a power supply which outputs a voltage for powering the transponder in response to the power signal. The information generating circuit includes a reprogrammable EEPROM and an EEPROM interface circuit which operates on the EEPROM by retrieving and storing data in response to the instructions and data contained within the first communication signal.