Switch input processing module for switching signal transmission lines to transmit different types of signals

A switch input processing module comprising:

• a control unit;
• an analog multiplex having a plurality of manually-operated switches;
• a serial multiplex having a plurality of manually-operated switches;
• a first external connection terminal;
• a second external connection terminal;
• an analog signal transmission line which is disposed between the first external connection terminal and the control unit;
• and
• a serial signal transmission line which is branched from the analog signal transmission line, the serial signal transmission line being made conductive or nonconductive under the control of the control unit;
• wherein the control unit receives via the second external connection terminal a determination signal indicating that the serial multiplex is connected to the first external connection terminal, and
• when the control unit determines that the determination signal indicates connection of the serial multiplex to the first external connection terminal, the control unit makes the serial signal transmission line conductive and receives a serial signal indicating operating state of the plurality of manually-operated switches of the serial multiplex via the serial signal transmission line.