Patent ID: 7187692
Filing Date: 2007-03-06
Classification: G06K

Abstract:
1. An information communication system including a master station and a plurality of slave stations which perform contactless communication with the master station, wherein each slave station comprises: reception means for receiving a signal from the master station; transmission means for transmitting a response signal in response to the signal from the master station; time slot determining means for determining a time slot used to transmit the response signal; time delay determining means for determining a delayed time for transmitting the response signal within the determined time slot by selecting one out of a plurality of predetermined transmission delayed times; detecting means for detecting a transmission of a response signal by another slave station having been performed prior to the determined delayed time within the same time slot; and response signal transmission control means for controlling not to transmit the response signal if the detecting means detects the transmission of the response signal, wherein a time duration ΔTd between each delayed time is set to such a time duration as is enough for the detecting means to detect that another slave station has transmitted a response signal, and is represented by the following formula: where ΔTs represents a time period of one time slot, and N the number of delayed times.