Abstract: An earphone detection circuit that comprises a transistor, a first resistor, a second resistor, a third resistor and a detector. The transistor has a first terminal, a second terminal, a third terminal and a fourth terminal. The first and the fourth terminal of the transistor are electrically connected to an operating voltage. One end of the first resistor is electrically connected to the first terminal of the transistor and the other end of the first resistor is electrically connected to the second terminal of the transistor. One end of the second resistor is electrically connected to the third terminal of the transistor and the other end is electrically connected to a ground terminal. One end of the third resistor is electrically connected to the second terminal of the transistor and the other end is electrically connected to the detection terminal of an earphone driving circuit.

Abstract: An earphone detection circuit that comprises a transistor, a first resistor, a second resistor, a third resistor and a detector. The transistor has a first terminal, a second terminal, a third terminal and a fourth terminal. The first and the fourth terminal of the transistor are electrically connected to an operating voltage. One end of the first resistor is electrically connected to the first terminal of the transistor and the other end of the first resistor is electrically connected to the second terminal of the transistor. One end of the second resistor is electrically connected to the third terminal of the transistor and the other end is electrically connected to a ground terminal. One end of the third resistor is electrically connected to the second terminal of the transistor and the other end is electrically connected to the detection terminal of an earphone driving circuit.

Abstract: A method for answering a call from a remote terminal with a smart phone. The method comprises the steps of pre-storing a sound clip in the smart phone, receiving the call and acquiring a caller identity delivered therewith from the remote terminal, generating a selection signal corresponding to the caller identity, and selecting a voice signal derived from a microphone or from the sound clip to be transmitted to the remote terminal according to the selection signal.