Patent ID: 6040786
Filing Date: 2000-03-21
Classification: G06K

Abstract:
A recognition system for non-contact IC cards comprising a plurality of non-contact IC cards and a reader/writer that recognizes said non-contact IC cards,each of said non-contact IC cards having a first response signal transmitting means for immediately transmitting a first response signal to a predetermined time slot in response to a first polling trial by said reader/writer and a second response signal transmitting means for transmitting a second response signal to a time slot randomly selected from a predetermined number of succeeding time slots, in response to a subsequent polling trial by said reader/writer andsaid reader/writer having a polling means for receiving the first response signal from each of said non-contact IC cards at the predetermined time slot during the execution of the first polling trial and receiving respective second response signals from said non-contact IC cards at the predetermined number of succeeding time slots during the execution of the subsequent polling trial.