Hand-free system capable of preventing a vehicle's automatic antenna from random operation

A hand-free system for use on a cellular phone being operated in combination with a vehicle's audio stereo system, capable of preventing a vehicle's automatically operated antenna from being randomly extended or retracted in correspondence to operation conditions of a cellular phone, comprising an electronic switch, a power source and charging circuitry, an amplifier and acoustic quality processing circuitry, an acoustic source control CPU and an antenna controlling circuitry, and said operating in cooperation with an antenna of a vehicle;

• wherein said hand-free system is characterized by that when a cellular phone is receiving incoming signals, said acoustic source control CPU will transmit a control signal to said antenna control circuitry which detects the antenna being lifted or lowered first and then send off a relay responsible for control of a lifting or lowering operation on said antenna to maintain said relay in operation;
• till said cellular phone terminates its communication operation, control of said antenna is returned to said vehicle's audio stereo system whereby said antenna is protected from being randomly extended and retracted in response to turn-on and turn-off operations of said vehicle's audio stereo system.