| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable a process needing a time longer than transmission time to and from a passive type RF tag to be performed even when the transmission time of a carrier is limited. <P>SOLUTION: Reader-writers RW1, RW2 performs a carrier detection process before transmitting the carrier, starts transmission of the carrier in an empty channel area in which the carrier is detected, stops the transmission of the carrier within a predetermined transmission time T0 after starting the transmission of the carrier, and stops the transmission of the carrier within the predetermined stop time T1 after then. When the reader-writers RW1, RW2 have a common communication range, electric power is continued to be successively supplied within a period exceeding the transmission time T0 relating to the RF tags TAG1, TAG2 existing within the common communication range by transmitting the carrier by at least one of the reader-writers. <P>COPYRIGHT: (C)2008,JPO&INPIT |
