Abstract: A hierarchical structure is established among a plurality of RFID tags, such that ID numbers can be read only from RFID tags which belong to a particular layer. RFID tag can control whether permission should be given to read its ID number therefrom to protect the ID number. Data held in the RFID tag can be read from the outside. RFID tag comprises a memory circuit having a function of holding data, and a logic circuit having a function of processing a control command received from outside. Memory circuit stores an own ID number for identifying the RFID tag itself, and a parent ID number for identifying a second RFID tag. When RFID tag receives an ID number read command which contains first data as a parameter from outside, the logic circuit outputs the own ID number to outside only when the first data matches the parent ID number.

Abstract: A hierarchical structure is established among a plurality of RFID tags, such that ID numbers can be read only from RFID tags which belong to a particular layer. RFID tag can control whether permission should be given to read its ID number therefrom to protect the ID number. Data held in the RFID tag can be read from the outside. RFID tag comprises a memory circuit having a function of holding data, and a logic circuit having a function of processing a control command received from outside. Memory circuit stores an own ID nmber for identifying the RFID tag itself, and a parent ID number for identifying a second RFID tag. When RFID tag receives an ID number read command which contains first data as a parameter from outside, the logic circuit outputs the own ID number to outside only when the first data matches the parent ID number.

Abstract: A frame for use in a seat for a vehicle such as an automobile is disclosed which can be placed directly on a floor of a vehicle and also can be removed from the vehicle floor by hooking a fingertip on it. In this frame, the inner edge of the frame on which the fingertip is to be caught is foldedly formed into a right-angle shape so as to prevent the fingertip against damage, and the frame is inclined higher in its inward direction to prevent springs from coming into contact with the frame even when they are flexed due to application of loads.