An apparatus has a plurality of types of plugs used for different purposes and a plurality of circuit board assemblies. Each of the plurality of the circuit board assemblies includes a circuit board having a plurality of wiring portions formed thereon, an electrical and electronic part mounted on the circuit board, and a plurality of sockets attached to the circuit board and connected to the electrical and electronic part via the plurality of wiring portions. The sockets included in all of the plurality of circuit board assemblies have the same shape and are configured to receive any of the plurality of types of plugs.