A detection switch mounted in a card socket including contact members responsive to insertion of a card into the card socket. The sideplates expand to allow spindles and spools to be installed within openings of the housing. The LEDs may be powered by a battery, an external power source, or both. Whether a change in magnitude of the FSR output during a time interval is greater than a threshold is determined. A circuit control unit controls the impedance of the selected circuit so that the value of the evaluation function proportional to the product of the first reception power and the second reception power becomes larger. The conditions to which the damaged site and the test site are subjected are substantially the same.