"The fourth state depicted in FIG. 2A is a state where the second housing 12 (together with the third housing 13) slides in the ???X direction with respect to the first housing 11 from the position at which the second housing 12 is located in the third state depicted in FIG. 1C. In this state, the full keyboard 14 and the ten-key keypad 15 appear (become exposed)." . . . .