An improved telephone system over a single telephone line within a residence or other building is disclosed, supporting exchange features and enabling easy expansion for multiple external lines. When the voltage becomes not more than a reference value, the controller controls the current supplied to the actuator so as to become lower than a current set in advance, depending on consumption power of the actuator, in a case that the consumption power of the actuator is not less than a specified value set in advance. These lugs respectively have a first clevis hole and a second clevis hole. The nanoparticles include a catalyst material coupled to one or more ligands, and these nanoparticles are disposed within respective recesses of the substrate.