| 摘要 |
PURPOSE:To easily find out the portable telephone set even in the case of missing or misplacing by comparing an electric field strength of a specific signal with a threshold level stored in a memory and using a light emitting section and a speaker so as to inform it when the electric field intensity is smaller. CONSTITUTION:A control signal generated from a control signal generating section 17 of a control signal generator 16 is sent from a transmission section 18 via an antenna 19. Then the control signal received by a reception section 19 via an antenna 9 of the portable telephone set 8 is inputted to an electric field intensity measurement section 11. The electric field intensity of the control signal is measured by the section 11 and the electric field intensity is compared with a threshold level stored in advance in a memory 12. When the electric field intensity is less than the threshold level, the electric field intensity measurement section 11 sends a signal to activate a control section 13, then a sound is outputted from a speaker 15 or a light emitting section 14 lights up an LED. Thus, a control signal generator 16 is carried, then it is informed to the possessor when the distance between the generator 16 and the portable telephone set 8 is apart over a prescribed distance and missing is prevented. |
