First, notebook computers usually use colors to distinguish USB2.0 and USB3.0 interfaces. USB2.0 is usually white or black, while USB3.0 is usually blue. Second, USB interface: UniversalSerialBus is a brand-new computer interface technology, which has the characteristics of fast transmission speed, hot plug support and simultaneous connection of multiple devices. At present, there are three USB interfaces: USB 1. 1, USB2.0 and USB3.0, which are backward compatible; Theoretically, the transmission speed of USB 1. 1 can reach 12Mbps, while USB2.0 can reach 480Mbps and USB3.0 can reach 5.0Gbps. Schematic diagram of USB2.0 interface: IV. Schematic diagram of USB3.0 interface: V. Various USB interfaces: