| 摘要 |
PROBLEM TO BE SOLVED: To perform data transmission without any interference with respective data carriers when many data carriers are present in a communication area. SOLUTION: A reader writer 12A accesses data carriers 11 while limiting the number of data carriers whose response are acknowledged among object data carriers 11 of data communication. When there is no data carrier 11 meeting the conditions, the response conditions are changed and a similar processing is repeated. Consequently, even when many data carriers 11 are present in the communication area, a data communication with data carriers can be made without any interference. |
