A folder apparatus includes a folder, a holder for holding leaves and a connector for attaching the holder to the folder in a detachable manner. The present invention is capable of carrying out a reliable screening of defective pixels so as to effectively avoid deterioration in reliability even in cases where transistors with low withstand voltages are employed. In one aspect, an apparatus and method for testing a PCI device for compliance under the PCI specification in target operation is provided. The switching system has a facility for storing all subscriber-related information as a plurality of transient subscriber service images defining the services and features to be provided for subscribers having pending or active calls.