Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad variety of USB hardware exists, including 14 different connector types, of which USB-C is the most recent and the only one not currently deprecated. First released in 1996, the USB standards are maintained by the USB Implementers Forum (USB-IF). The four generations of USB are: USB 1.x, USB 2.0, USB 3.x, and USB4. Overview USB was designed to standardize the connection of peripherals to personal computers, both to communicate with 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. Examples of peripherals that are connected via USB include computer keyboards and mice, video cameras, printers, portable media players, mobile (portable) digital telephones, disk drives, and network adapters. USB connectors have been increasingly replacing other types as charging cables of portable devices. Connector type quick reference Each USB connection is made using two connectors: a socket (or receptacle) and a plug. In the following table, schematics for only the sockets are shown, although for each there is a corresponding plug (or plugs). Objectives The Universal Serial Bus was developed to simplify and improve the interface between personal computers and peripheral devices, such as cell phones, computer accessories, and monitors, when compared with previously existing standard or ad hoc proprietary interfaces. From the computer user's perspective, the USB interface improves ease of use in several ways: The USB interface is self-configuring, eliminating the need for the user to adjust the device's settings for speed or data format, or configure interrupts, input/output addresses, or direct memory access channels. USB connectors are standardized at the host, so any peripheral can use most available receptacles. USB takes full advantage of the additional processing power that can be economically put into peripheral devices so that they can manage themselves. As such, USB devices often do not have user-adjustable interface settings. The USB interface is hot-swappable (devices can be exchanged without rebooting the host computer). Small devices can be powered directly from the USB interface, eliminating the need for additional power supply cables. Because use of the USB logo is only permitted after compliance testing, the user can have confidence that a USB device will work as expected