Method and apparatus for reducing power consumption in a digital specific signal processor integrated circuit. A wristwatch is equipped with a vent valve mounted to a timepiece exterior assembly. A width of the second area is more than a width of the first area, and an acoustic capacitance of the second area, per unit length in the paper feeding direction is higher than an acoustic capacitance of the first area, per unit length in the paper feeding direction. Each signal contact forms a second engaging portion and a second contacting portion.