摘要 |
A wireless tag reader/writer apparatus according to this invention includes a receiving/transmitting antenna configured to transmit an interrogation signal to wireless tags, each having a storage unit with at least a reserved area and an EPC area for storing a group ID unique to the wireless tag, and configured to receive response signals from the wireless tags; a tag-data storing unit configured to store interrogation data and response data, the interrogation data being contained in the interrogation signal to be transmitted to the wireless tags, and the response data being contained in the response signals transmitted from the wireless tags; and a main control unit configured to detect the group ID stored in the reserve area of each wireless tag, from the response data stored in the tag-data storing unit, and configured to determine that at least one of the wireless tags has dropped out, from the number of group IDs stored in the reserved area of each wireless tag.
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