The invention discloses a method for establishing a
single line connection, and relates to the technical field of portable listening devices. The method is used for solving the problem that the communication between an existing
wireless earphone and a charging box is unreliable, which is not conducive to the user experience. The method comprises the following steps: judging, by a
wireless earphone, whether a power supply contact point of a charging box is in a communication mode, wherein a charging contact point of the
wireless earphone is connected with the power supply contact point of the charging box; and if yes, switching the charging contact point from a charging mode to the communication mode, and establishing the
single line connection with the charging box. According to the methoddisclosed by the invention, the charging contact point of the wireless earphone is connected with the power supply contact point of the charging box to establish the
single line connection between the wireless earphone and the charging box, so that the wireless earphone and the charging box can perform information interaction through the single line connection, thereby improving the communicationreliability of the charging box and the wireless earphone, and improving the user experience. In addition, the invention further discloses an apparatus for establishing the single line connection, awireless earphone, a TWS earphone and a charging box, which also have the above beneficial effects.