Patent ID: 7889058

Claim:
A radio-tag reading system comprising: a plurality of radio tags each configured to be attached to an object and stores therein respective radio tag information, the respective radio tag information being predetermined information on the object; and a radio-tag reader that reads the respective radio tag information from each radio tag, and includes: a communicating unit that performs radio communication with each radio tag; a radio-tag detecting unit that transmits via the communicating unit a search signal at predetermined time intervals, the search signal having a field that includes a command to one or more radio tags in the communication area to each transmit a response signal according to a predetermined condition, and wherein the radio-tag detecting unit detects at least one of movement of the one or more radio tags into and out of the communication area where radio communication is available through the communicating unit based on the response signals transmitted from the one or more radio tags satisfying the predetermined condition to the search signal; and a radio-tag information processing unit that responsive to detecting said at least one of movement of the one or more radio tags into and out of the communication area, reads the respective radio tag information from the one or more radio tags upon receiving the response signals from the one or more radio tags according to said predetermined condition; wherein the radio-tag detecting unit generates the search signal that includes the command to reduce a transmission rate of the response signals from the one or more radio tags by a predetermined percentage, and one or more responding units of the one or more radio tags transmit the response signals while reducing the transmission rate by the predetermined percentage based on the command.