Authorizing a billing by a billing system of a telephone network, to a subscriber, for a service requested over the Internet, using a calling card. Preferably the method includes imparting residual compressive stresses into the metal parts and uses various small ball type structures to create small compressions in the surfaces of the metal parts. The sealant joins the substrates together with the liquid crystal disposed between the substrates. An incompatible device display part performs display for specifying an audio processing device that stores a firmware that does not satisfy compatibility defined in the matching table with a firmware stored in the reference device.