| 摘要 |
<p>PURPOSE:To perform the transfer of data by existing hardware as supplying a new clock in accordance with the standardization of the ISO to an IC card by supplying clocks of first and second frequencies to the IC card. CONSTITUTION:A card reader/writer 2 performs the transfer of the data with the IC card 1 by using a clock signal from a first oscillator 24. The first oscillator 24 generates the clock of, for example. 1200*2<n>, which enables the transfer of the data at transmission speed 9600bps via an I/O line 21 by applying 2<m> (m<=n)-frequency division to be performed. A second oscillator 25 generates a clock signal for operating the IC card, and generates a clock of frequency not being set at the multiple of 1200bps even when, for example, R<k> (k<=n)- frequency division for frequency 3.5712MHz for reset, etc., regulated by the ISO is applied. A frequency selection circuit 27 selects one of the frequencies from the second oscillator 25 and a frequency divider circuit 26 which frequency- divides the frequency of the first oscillator 24.</p> |
