Patent ID: 6021951
Filing Date: 2000-02-08
Classification: G06K

Abstract:
A wireless IC card system having a card reader and an IC card, said IC card employing an antenna for transmitting data to an antenna of said card reader, comprising:oscillation means, provided for said card reader, for generating an alternating current signal as a carrier;switching means, connected to said antenna of said IC card; control means, provided for said IC card, for controlling said switching means in accordance with the contents of data to be transmitted to said IC card reader, so that an alternating current property of said IC card is changed, and for selectively changing a load imposed on a transmission system between said IC card and said card reader to a first state or to a second state;reflected wave detection means, provided for said card reader, for detecting a reflected wave that occurs in said transmission system in accordance with said load; and data identification means, provided for said card reader, for employing a detected reflected wave to identify said data to be transmitted.