| 摘要 |
PURPOSE:To attain the data writing/reading of only one data carrier even when two or more data carriers are approached to a reader/writer in the data writing/reading system of a data carrier for writing/reading out data in/from a memory in accordance with an access from the reader/writer connected by electromagnetic induction. CONSTITUTION:A common code string common to all data carriers 20 and inherent code strings different in each data carrier 20 are stored in a non- volatile memory 24, and at the time of receiving a common code string sent from the reader/writer 10, the common code string stored in the memory 24 is read out and collated with the received data. When both common code strings coincide with each other, the reader/writer 10 is allowed to read out the inherent code string and return the read contents, and at the time of receiving the read inherent code string, the common code string is read out of the reader/writer 10 and collated, and writing is allowed when both the code string coincides with each other, or writing is inhibited when unmatch is generated between both the code strings. |
