| 摘要 |
<p>PURPOSE:To make it possible to send and receive data to and from an IC card without being affected by surface staining or dust on the IC card by providing an interface using an audio signal for inputting and outputting data to and from the IC card. CONSTITUTION:An audio signal is used for interface between an IC card and a system side. A microphone is used to receive an audio signal, and consists of a piezoelectric element. A speaker SPK is used to send an audio signal, and this is also made of a piezoelectric element. A microcomputer MCU applies frequency modulation, phase modulation, or the like to an audio signal having a constant frequency to superpose information, and demodulates the received audio signal to read information. Thus, by using an audio signal to input output data, sending and receiving data can be achieved surely without being affected by surface staining, dust or the like on the IC card.</p> |
