| 摘要 |
PURPOSE:To provide the portable telephone set in which key operation is easy even at a dark place and the power consumption is minimized. CONSTITUTION:A portable telephone set 1 is provided with light emitting elements 16A-17I lighting up keys 14A-15I, a detection element 181 detecting the lightness of the surrounding of the portable telephone set 1 and a detection means 191 detecting the operating state of the portable telephone set 1. The light emitting elements 16A-17I are lighted to light up the keys 14A-15I only when the surrounding is dark and the portable telephone set 1 is in use based on a detection output SC of the detection element 181 and the detection output SS of the detection means 191. |
