The Colors And Meanings Of The Four Wires in A USB Data Cable

The USB data cable, particularly the USB 2.0 standard cable, typically contains four wires with different colors and functions.

The following are the color codes and uses for these wires:

Red (Vcc or V+): Represents the power positive. This wire is used to provide power to the device and has a voltage of +5V.

Black (GND or V-): Represents the ground. This wire acts as both the return path for the power and the reference ground for the signals.

Green (D+): Represents the data positive. This wire is used for transmitting the positive signal for data transfer.

White (D-): Represents the data negative. This wire is used for transmitting the negative signal for data transfer.


Working Principle Overview:
USB data transmission is based on differential signal technology, which uses a pair of wires (D+ and D-) to send data. When a device sends data, it applies voltage changes that are opposite in direction to the D+ and D- lines. The receiving end then detects the voltage difference between these two lines to restore the original data signal. This method is effective in resisting interference and improving data transmission reliability.

Other Considerations:
USB 3.0 and above versions: USB 3.0 introduces additional wires for high-speed data transmission, so USB 3.0 cables have more wires inside. In addition to the original four wires, two pairs (four) of differential signal wires are added for high-speed data transmission.
Color coding may vary: Although the above color coding is a common configuration, not all manufacturers strictly adhere to this standard. In some cases, colors may vary, so please refer to the specific device manual or use a multimeter to confirm the wire function during maintenance or DIY projects.