| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce power consumption of an active non-contact information storage device. <P>SOLUTION: In this information access system, a reading/writing apparatus (300) transmits an ID request signal of a first frequency (f<SB>1</SB>) and takes the continuous reception wait state of an RF signal of a second frequency (f<SB>2</SB>), and the active non-contact information storage device (200) comprises a control part, a battery, a receiving part for performing carrier sense of a first frequency RF signal and a transmitting part for transmitting a second frequency response signal when receiving the ID request signal. The receiving part performs carrier sense of the first frequency RF signal during the prescribed term of a first cycle in a first mode. When the receiving part does not detect the first frequency RF signal during a certain prescribed term, the receiving part and the transmitting part become an inactive state up to the prescribed term of the next carrier sense. When the receiving part detects the first frequency RF signal, the receiving part receives the ID request signal to shift to a second mode. The receiving part becomes an inactive state in the second mode, and the transmitting part transmits a second frequency RF signal including an ID in each prescribed time term of every cycle, transmits the second frequency RF signal two times or more and shifts to the first mode. <P>COPYRIGHT: (C)2007,JPO&INPIT |
