PURPOSE: To cause no output error when a package is drawn out, by supplying an electric power supply and a lock signal from an external connector.

CONSTITUTION: External connectors 17, 18 are provided on a package, and an electric power supply and a lock signal are applied from said connectors. At first, when the package is drawn out, the electric power supply and the lock signal are applied from the external connectors, so that an output error is not caused when the package is drawn out. When it is inserted, too, the electric power source and the lock signal are applied from the external connectors, and after that, it is inserted. Also, the external connector is provided with a connector terminal 25 for a lock signal 23, + electric power supply terminal 24, 27 and a "O"V terminal 26, and by combination of 2 + electric power supply terminals and a capacitor C, it is prevented that a load current changes suddenly when the external connector is inserted or drawn out. Also, when 2 middle terminals among the 4 terminals are made to "O" V, even if the external connector 18 is inserted in reverse, the electric power supplies of (+) and "O"V are not short-circuited.