| 摘要 |
PROBLEM TO BE SOLVED: To provide a mobile phone that has a missing (theft) preventing function of itself. SOLUTION: The electric field strength of a 2nd radio wave sent from both the mobile phone and its slave unit is measured to detect that the mobile phone and its slave unit are apart from a closest distance to transmit a warning tone or the like. Thus, when the mobile phone of the user is missing (stolen), the user can quickly recognize it. |
