| 摘要 |
<p>PURPOSE:To exactly judge the remaining quantity of a battery by providing a judging means for judging the remaining quantity of a battery of a card-like device, based on a photodetecting output of a photodetecting means. CONSTITUTION:Data is transmitted and received between a card-like device 1 and a main body 5. Transmitting data of a card type terminal 1 is transmitted as an optical output from an LED 9, made incident on a phototransistor 27 of the main body 5, and the main body 5 receives it. The LED 9 is driven by using a battery 15 as a power source. Accordingly, the optical output emitted from the LED 9 drops as a voltage of the battery 15 drops. Also, the phototransistor 27 converts photoelectrically the light emitted from the LED 9, and outputs a voltage being proportional to the optical output to an emitter terminal 27-a. An A/D converter 25 A/D-converts a voltage level of the emitter output 27-a, and outputs it as digital information to a control part 7. By said operation, the control part 7 can detect the voltage of the battery 15 of the card type terminal 1.</p> |
