A request to generate a first key may be received. The circuit includes a plurality of analog-to-digital converters arranged in parallel. Secondly, step is performed to receive a first answer inputted by a user. A second member of the first planetary gearset is continuously interconnected with a first member of the third planetary gearset. A flexible, durable tee shaft extends down to a cylindrical and conically shaped anchor with a flat bottom. When an inspection signal is supplied from the printing apparatus to the first terminal, the inspection circuit outputs an output signal according to the inspection signal.