An optical fiber ribbon comprising a plurality of the coated optical fibers 2 arranged in plane and flame-retardant films 4a and 4b to integrate the coated optical fibers 2 is provided. A client provides a server with information about files that are on it together with what it knows about these files. The electrical signals from each piezoelectric cable are analyzed by a processing system to determine event classification and location. Then, the information designated by the designation information received in response to the transmission of the selection information is transmitted to the external apparatus via the communication medium.