Function
USB is a technology that supports data transfer to devices such as computers, televisions or printers from a variety of devices including, but not limited to, computer mouses, cameras, cell phones, MP3 players, external hard drives and memory sticks or thumb drives. The USB port is the interface into which you plug your USB cable or device on your computer. Typically, computers contain one or more USB ports for use with devices.
Benefits
Because USB technology supports plug and play usage, you do not have to install separate software when you first connect your device, although the device manufacturer may include software with the device. If your device requires a driver (a small program that allows the computer and connected device to communicate properly), your operating system will attempt to locate and install this driver automatically. USB cables and ports use several standard sizes or designs; thus, you may be able to use the same cable for multiple USB devices if your devices have the same ports.
Identification
You can recognize USB plugs or ports by the USB trident logo. The prongs end with a circle, triangle and square (from top to bottom). There are several standard USB port and plug styles. Type "A" plugs (and ports) appear long and narrow from the front but have a rectangular shape from the top or bottom. Traditionally, the USB ports on a computer are type "A" and the type "A" end of a USB cable inserts into this port. Type "B" USB ports are more square in shape; however, the top is similar to the top half of a hexagon, rather than a square. Printers frequently incorporate Type "B" USB ports. "Mini-B" and "Micro-B" USB ports are common on smaller devices, such as cell phones or digital cameras, because they are smaller in size.
Classifications
USB technology has improved over the years and you can purchase devices, computers and cables that take advantage of these improvements. As of March 2011, USB 3.0 is the most recent classification, allowing for data transfer at speeds of up to five gigabits per second. This is more than ten times an improvement over USB 2.0, which features maximum transfer speeds of 480 megabits per second and USB 1.1 which can only transfer data at 12 megabits per second. USB 3.0 and 2.0 are both backwards compatible; however, pairing a USB 3.0 device with a computer that only supports an earlier standard will result in reduced data transfer speed.
