Patent ID: 7580724

Claim:
A communication system comprising: an IC tag attached to an object; a reader/writer provided with a function for communicating with the IC tag for a predetermined time; a mobile information terminal for carrying the reader/writer; wherein the mobile information terminal comprises the functions of: a first alarm emission function for emitting a first alarm when communication with the reader/writer and the IC tag becomes impossible; a second alarm emission function for emitting a second alarm when communication with the reader/writer and the IC tag becomes possible; a position information acquisition function for acquiring a position information of the mobile information terminal when communication with the reader/writer and the IC tag becomes impossible; and a display function for displaying the position information acquired by the position information acquisition function, wherein said first alarm and said second alarm are different and are selected from the group of alarms consisting of sound, luminescence, vibration and screen information, or its combination, and wherein the setting change is arbitrarily possible from the mobile information terminal.