The USB is a fast, bidirectional, synchronous, inexpensive, and convenient hot-pluggable serial interface widely used for its advantages in data transfer speed, easy interface, and hot-swapping support. Proper PCB layout adhering to USB signal rules is crucial for stable operation of USB devices. Key points include keeping differential line length short, avoiding excessive vias, using symmetrical and parallel wiring, controlling line length mismatch within 5mil, maintaining distance from other signal networks, and ensuring proper line width and impedance for high-speed USB devices operating at 480 Mbits/s. Applying these guidelines will guarantee the reliable performance of USB devices.