Patent ID: 7374089

Claim:
An IC-tag read-write apparatus comprising: a plurality of first antennas configured to perform a one-to-one radio communication with a plurality of second antennas of IC tags having respective different communication frequencies; a plurality of modulation circuits corresponding to the plurality of first antennas and each configured to modulate a carrier wave in accordance with data to be transmitted and transmitting the modulated carrier wave to a specific IC tag among the plurality of IC tags, in accordance with a specified communication protocol, through a corresponding one of the plurality of first antennas; a carrier wave generating circuit configured to generate a plurality of carrier waves having respective different frequencies; a memory storing for each one of the IC tags, communication information including parameters indicating a resonance frequency assigned to the IC tag and one or more communications protocols used by the IC tag; and a control circuit configured to read from the memory a specific resonance frequency assigned to a target IC tag among the IC tags, generate a control signal, and read from the memory communications protocols data indicating the one or more communications protocols used by the target IC tag; a switch circuit configured to exclusively select one of the plurality of carrier waves from the carrier wave generating circuit in accordance with the control signal generated by the control circuit, wherein said control signal causes the switch circuit to select a specific carrier wave having a radio frequency substantially equal to the specific resonance frequency read from the memory, and supplies the communications protocols data indicating the one or more communications protocols used by the target IC tag, along with the specific carrier wave and data to be transmitted in synchronism with each other, to a corresponding one of the plurality of modulating circuits.