| 摘要 |
A method for cutting off power during call communication by a handsfree is provided to prevent discharge of a battery by connecting a register to a main power battery, a microcomputer and a DSP chip of a handsfree system to maintain a call connection state when power is cut off. When a call is available(S1), a microcomputer checks whether power of a start switch of a car is not lower than 5V(S2). If the power of the start switch is lower than 5V, the microcomputer checks whether a voltage signal is generated from a mobile phone jack(S4). If no voltage signal is generated, the microcomputer cuts off power(S5), whereas if a voltage signal is generated from the mobile phone jack, the microcomputer transmits a voice warning message through a speaker(S6). A timer counts a pre-set time(S7). The microcomputer checks whether a power re-input signal of the start switch is inputted during the pre-set time(S8). If power of the start switch is not re-inputted, the microcomputer cuts off power(S10) and call communication is terminated(S11).
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