| 摘要 |
PURPOSE:To provide a radio card repetitively usable over a long period by providing it with a charging function by the use of radio waves and charging a built-in battery when the battery runs down. CONSTITUTION:In the radio card 1 provided with a radio communication means started through the reception of a start signal sent through a radio channel from a card reader/writer and sending/receiving data with the card reader/writer through a radio channel and incorporating a chargeable battery 18 charged as an operating power supply, when a CPU 15 receives the start signal from the card reader/writer, the CPU 15 senses a voltage of the battery 18 via an A/D converter section 19 and allows a display section 2 to display that the charging is required for the battery 18 when the sensed voltage of the battery 18 is less than a predetermined value. After the necessity of charging is displayed on the display section 2, the charging radio wave is received by inserting the radio card 1 to a radio wave charger, the received radio wave is rectified by a rectifier section 17 to charge the battery 18. |
