< span style="font-family: Roboto;">USB (Universal Serial Bus) is a standard for connecting devices to a computer. It is a plug-and-play interface that allows devices to be connected and disconnected without the need to reboot the computer or configure device drivers. USB cables are widely used to connect devices such as keyboard, mouse, printers, digital cameras, flash drives, and external hard drives to a computer. 

There are several different versions of USB, including USB 1.1, USB 2.0, USB 3.0, USB 3.1, USB 4.0. The main difference between these versions is the data transfer speed and power delivery capability. USB 1.1 and 2.0 have a maximum data transfer speed of 480Mbps, while USB 3.0 and 3.1 offer a maximum data transfer speed of 5Gbps. USB 4.0 offers a maximum data transfer speed of 40Gbps. 

USB cables also come in different types, such as Type A, Type B, Mini-USB and Micro-USB. The Type A connector is typically found on computers and other host devices, while the Type B connector is typically found on devices such as printers and scanners. Mini-USB and Micro-USB connectors are commonly found on mobile devices such as smartphones and tablets.