(1) See
USB drive and
USB port.
(2) (
Universal
Serial
Bus) A hardware interface that supports up to 127 peripherals. USB is used to attach keyboards, mice, printers, external storage and mobile devices to the computer. It is also used for charging a wide variety of portable products (see
USB power). Governed by the USB Implementers Forum (see
USB-IF), USB emerged in the mid-1990s and soon replaced the earlier
serial port,
parallel port and
Apple Desktop Bus.
Hot Swappable Drives
USB devices can be plugged and unplugged while the computer is on. This feature, combined with easy-to-reach ports on every computer, gave rise to the ubiquitous USB drive for transport (a manual "eject" is however required). See
USB drive,
USB device class,
USB OTG,
USB switch and
USB toy.
Connecting via USB
Host sockets are Type A, and peripherals use B, Micro-B, Mini-B, USB-C and Lightning. In time, USB-C is expected to replace A, as well as every other USB connector. Today, some laptops have only USB-C ports, while all other computers have Type A. See
USB Type C,
USB hub,
Mini USB,
Micro USB and
Lightning connector.
SuperSpeed Logos
As of USB 4, the nomenclature was simplified so that future SuperSpeed logos show their speed ratings (5, 10, 20, 40) and eventually replace the multiple designations for USB 3.x (see
USB 3.2). DisplayPort requires USB-C cables (see
USB Type C).
USB 2.0 Data Rate
USB 2.0 High Speed 480 Mbps
USB 2.0 Full Speed 12 Mbps
USB 2.0 Slow Speed 1.5 Mbps
USB 3.2 Data Rate Lanes
SuperSpeed
USB 3.2 Gen 1x1 5 Gbps 1
(a.k.a. USB 3.0)
(a.k.a. USB 3.1 Gen 1)
SuperSpeed+
USB 3.2 Gen 2x1 10 Gbps 1
(a.k.a. USB 3.1
(a.k.a. USB 3.1 Gen 2)
USB 3.2 Gen 1x2** 10 Gbps 2
USB 3.2 Gen 2x2** 20 Gbps 2
USB 4 40 Gbps 2
** Dual-lane requires USB-C cables
USB Is Often Power Only
USB is widely used as a power source for phones, tablets and other devices. This Chromecast streaming stick plugs into the TV's HDMI port but is powered by USB (see
Chromecast and
USB power).
(Image courtesy of Google Inc.)