The USB protocol (Universal Serial Bus) is a standard that allows computers and devices to communicate and transfer data. It defines the types of connectors, cables, and communication methods used for connecting peripherals like keyboards, mice, and external storage devices. USB supports various data transfer speeds, making it versatile for different applications. Introduced in the mid-1990s, the USB protocol has evolved through several versions, including USB 1.0, USB 2.0, and USB 3.0, each offering improvements in speed and functionality. It also supports power delivery, enabling devices to charge while connected, enhancing convenience for users.