Universal Serial Bus is an almost ubiquitous standard for connecting devices like mice, keyboard, joysticks, printers, scanners, card readers, etc. to computers without switching off the system. USB comes in two versions—1.1 and 2.0, while a 3.0 standard is under development. These standards are based on speed. USB 1.1 transfers data at 1.5 to 12 Megabits per second, while USB 2.0 transfers data at 480 Megabits per second. USB 3.0 is projected to transfer data at a maximum rate of 4.8 Gigabits per second. A computer can connect to a maximum of 127 USB devices directly or by using hubs.
USB connectors are of two types—the A connector and the B connector. Most devices come with their own USB cables and they use the A connector to connect to the computer. Devices that don’t have their own USB cables, like digital cameras, have a slot for the narrower B connector for connecting them to the computer.
There are other variants of USB connectors, like MiniUSB, MicroUSB, and Wireless USB. MicroUSB and MiniUSB are used in smaller devices like mobile phones, while Wireless USB is a short-range, high-bandwidth data transfer standard using USB’s radio platform. Wireless USB is used in game controllers, digital cameras, printers, scanners etc. It is also used for streaming video.