1, the line at both ends of the interface is the power line (standard is red 5V, black grounding), and the middle is the data line (green positive white negative).
2, the color of different usb data lines will be different, some are white, black power supply plus or minus, red and green data plus or minus, some are red and black power supply plus or minus, white and green data plus or minus, and there are yellow lines, in short, you must use a multimeter to measure before wiring.
The outer two pins of the charging interface are the positive and negative terminals of the power supply, the red line is connected to the positive terminal of the charger, and the black line is connected to the negative terminal of the charger.
Red on red, white on black.
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Extended data
Mobile phone data line working principle theory
In RS232C, -5V to -15V represents 1, and 5V to 15V represents 0; In TTL circuits, more than 3V represents 1, and less than 0.2V represents 0. The MAX232 integrated circuit realizes the conversion of RS232C and TTL circuits, in which the ⑧ pin receives the TXD(transmit data) signal sent by the 3 pins of the serial port, and outputs it from the ⑨ pin to the 6-pin IO-RXD of the mobile phone after conversion; ⑩ pin receives the IO_TXD signal from the mobile phone and outputs it to the 2-pin RXD and 1-pin DCD of the serial port. The MAX232 working power supply is provided by the serial port. After the 12V or so voltage output from serial ports 4, 6, 7 and 8 is rectified by two 1N14148 diodes, the 5V voltage output is stabilized by 78L05 regulator to the MAX232 pin for the integrated block to work.
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The 5V power supply is also sent to the 3 pins of the plug, which can charge the phone. If you do not want to use the charging function, you can solder 3 pins or add a small switch in the front. The four capacitive parameters of MAX232 affect the transmission speed of the data line, and the manufacturer's recommended value luF is used here. The 470uF and 47uF capacitors are power filter capacitors. If you want the circuit to have a data transmission indication function, you can add an indication circuit.
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If the heat is found to be serious, 7805 can be used instead, or 1V voltage regulator and current limiting resistor can be used instead. Capacitor welding should pay attention to distinguish between positive and negative electrodes. A 0.1uF CBB capacitor on both ends of the filter capacitor works better. The 4 parameter capacitors are best to use high-quality capacitors such as tantalum capacitors, and the capacity of luF or O.1uF can be selected according to the different integrated blocks. More difficult to find is the phone plug, but can be obtained from the same type of interface on the old charger, but pay attention to all metal pins must be complete. 6 core cable with shielding.
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Component selection: The core of this circuit is MAX232 integrated block, there are two common packages, one is double-in-line, slightly larger, easy to weld; The other is a patch type, smaller in size. In addition, if you cannot find MAX232, you can also use MAX232A, HIN232, MAX220, MAX3232, IL32 and other RS232 transceiver integration blocks instead, pin definition and MAX232 the same, the first two integration blocks faster. 78L05 appearance and ordinary triode, pay attention to ask the pin definition when buying.