| 摘要 |
PROBLEM TO BE SOLVED: To restrict outgoing and incoming calls of a portable telephone set placed in a mobile object while traveling without connecting the portable telephone set to a speed meter of the mobile object. SOLUTION: Fluctuation of an electric field strength of a radio signal received by an antenna 1 is detected timewise by a radio part 2, a mobile speed of the portable telephone set placed in a mobile object based on the fluctuation is obtained by using an arithmetic part 6, whether or not the portable telephone set is used in a vehicle while traveling is discriminated by the mobile speed and the outgoing/incoming calls by the portable telephone set are restricted by the result of discrimination. Furthermore, a current position 57 is detected through a radio wave from a GPS satellite by a position detection part 7, the mobile speed of the portable telephone set placed in the mobile body 5 is obtained by the arithmetic part 6 based on the current position 57, whether or not the portable telephone set is used in the vehicle while traveling through is discriminated based on the mobile speed and the outgoing/incoming calls of the portable telephone set are restricted based on the discrimination result. |
