Abstract: An RFID which provides a wide working voltage range and general versatility at low cost, without the need for changing its internal circuit design due to external factors. In the RFID, there is provided an arrangement that a low impedance state is given when its internal data communication circuit is in a reset state.

Abstract: A selective call receiver includes a receiver circuit for receiving calling information and message information, a processor for processing the calling information to determine whether the calling information identifies the selective call receiver, a message memory for storing the message information if the processor determines that the calling information does identify the selective call receiver, a message information output circuit for outputting the message information stored in the message memory to a portable data processing apparatus, a power receiving terminal for receiving power from the portable data processing apparatus, a rechargeable battery for powering the selective call receiver, a detector for detecting a state of charge of the rechargeable battery, and a charging circuit, responsive to the detector, for charging the rechargeable battery with the power received by the power receiving terminal from the portable data processing apparatus.