In-car telephone system, hands-free unit and portable telephone unit

Abstract

An in-car telephone system of great convenience is provided when switching between a hands-free conversation and a conversation using a handset of a portable telephone (a handset conversation), which has a portable telephone conducting wireless telephone communication and a hands-free unit, being connected to the portable telephone, which outputs a receiving voice from the portable telephone through a speaker arranged in a car and outputs an aural signal input from a microphone arranged in the car to the portable telephone as a transmitting signal. The in-car telephone system includes a connection detector to detect the communicative connection between the portable telephone and the hands-free unit during a handset conversation using a microphone and a speaker included in the portable telephone, and a mode switching device to switch from a handset conversation condition to a hands-free conversation condition using the microphone and the speaker arranged in the hands-free unit when the connection between the portable telephone and the hands-free unit during a handset conversation is detected by the connection detector.