| 摘要 |
PROBLEM TO BE SOLVED: To allow the user to make a speech by a portable telephone set in hand-free and in easy audible. SOLUTION: A connection plug 15 connecting to an earphone microphone terminal 10a provided for a portable telephone set 10 is connected to an FM transmission section 11 that modulates a voice signal received from a main body 1 via a connection cord 14 into an FM signal and outputs the modulated signal from an antenna 11a, to a control section 12 that is operated by detecting the input of the voice signal to control an FM transmission section, and to a transmission microphone 13. The transmitted FM signal is received by an antenna 2a of an FM receiver 2 provided to, e.g. an automobile, demodulated and heard as a sound from an in-vehicle speaker, then the sound volume and the sound quality are excellent. The device is driven by a small sized battery in the main body 1 and only when the control section 12 detects an incoming tone of the portable telephone set, power supply of the FM transmission section 11 is supplied and only when the reception voice signal is detected and the voice signal is received, the FM transmission section 11 is operated to reduce the power consumption and no hindrance is caused. |
