USB

Universal Serial Bus (USB)

Certified USB logo

The Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors, and protocols for connection, communication, and power supply between computers, peripherals, and other computers. USB was designed to standardize the connection of computer peripherals to personal computers, both to communicate and to supply electric power. It has largely replaced interfaces such as serial ports and parallel ports, and has become commonplace on a wide range of devices.

History

The development of USB began in 1994, with the goal of simplifying the connection of peripheral devices to a computer. The first USB standard, USB 1.0, was released in 1996. It provided a data transfer rate of 1.5 Mbit/s ("Low Speed") and 12 Mbit/s ("Full Speed").

Subsequent versions of USB have increased the data transfer rate and added new features. USB 2.0, released in 2000, increased the maximum data transfer rate to 480 Mbit/s ("High Speed"). USB 3.0, released in 2008, introduced a new transfer mode called "SuperSpeed" with a data transfer rate of up to 5 Gbit/s.

USB Connectors

USB connectors have evolved over time, with several types being used for different purposes.

USB Type-A

USB Type-A Receptacle White

The USB Type-A connector is the original design for the USB standard. It is a flat, rectangular interface that is commonly found on computers and other host devices. Type-A connectors are used for connecting peripherals such as keyboards, mice, and flash drives.

USB 3.0 Type-A Receptacle Blue

USB 3.0 introduced a new version of the Type-A connector, which is backward compatible with USB 2.0. The USB 3.0 Type-A connector is distinguished by its blue color.

USB Type-B

USB Type-B Receptacle

The USB Type-B connector is typically used on peripheral devices such as printers and external hard drives. It is a square-shaped connector with slightly beveled corners.

USB 3.0 Type-B Receptacle Blue

USB 3.0 also introduced a new version of the Type-B connector, which is backward compatible with USB 2.0. The USB 3.0 Type-B connector is also blue.

USB Type-C

USB Type-C MacBook

The USB Type-C connector is a newer design that is reversible, meaning it can be plugged in either way up. It is designed to replace both Type-A and Type-B connectors, and it supports USB 3.1 and USB 3.2 standards, which offer higher data transfer rates and power delivery capabilities.

USB Mini and Micro

USB Mini-A Receptacle

USB Mini and Micro connectors are smaller versions of the standard USB connectors, designed for use in portable devices such as smartphones, tablets, and digital cameras. The USB Mini-A connector is less common today, having been largely replaced by the USB Micro-B connector.

USB Power Delivery

USB has evolved to support power delivery, allowing devices to be charged over USB connections. The USB Power Delivery (USB PD) specification allows for higher power levels, enabling faster charging and the ability to power larger devices such as laptops.

Related Pages

• Serial port
• Parallel port
• FireWire
• Thunderbolt (interface)