Universal Serial Bus is a standard for attaching peripherals such as printers, scanners, mice, keyboards and other equipment to a computer. The original USB1.1 standard supports a rate of 12Mbps. Below on the left hand side is a USB plug. On the right, you’ll see the pins of the USB 1.1, 2.0 and 3.0 plugs.
USB 2 transfers data at about 480Mbps which is about 60 Megabytes per second. USB 2 is colour coded with black.
USB 3 transfers data at about 5 Gbps which is about 640 Megabytes per second. This makes them ideal for external hard drives and other high speed devices. USB 3 is colour coded with blue on the end of the plug.
USB C has a smaller connector that can be inserted either way up, and transfers data at about 10 Gbps or roughly 1.25 Gigabytes per second.
Read page 63-65 of the textbook “Exploring Computer Hardware”.