Universal Serial Bus (USB) is an industry standard that allows data exchange and delivery of power between many types of electronics. It specifies its architecture, in particular its physical interface, and communication protocols for data transfer and power delivery to and from hosts, such as personal computers, to and from peripheral devices, e.g. displays, keyboards, and mass storage devices, and to and from intermediate hubs, which multiply the number of a host's ports.
A network switch is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device.
ACCESS.bus, or A.b for short, is a peripheral-interconnect computer bus developed by Philips and DEC in the early 1990s, based on Philips' I²C system. It is similar in purpose to USB, in that it allows low-speed devices to be added or removed from a computer on the fly. While it was made available earlier than USB, it never gained the popularity of USB.
PCI Express, officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common motherboard interface for personal computers' graphics cards, capture cards, sound cards, hard disk drive host adapters, SSDs, Wi-Fi, and Ethernet hardware connections. PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism, and native hot-swap functionality. More recent revisions of the PCIe standard provide hardware support for I/O virtualization.
SATA is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PATA) standard to become the predominant interface for storage devices.
In computing, a docking station, port replicator (hub), or dock provides a simplified way to plug-in a mobile device, such as connect common peripherals to a laptop, or charge a smartphone. Because a wide range of dockable devices—from mobile phones to wireless mouse—have different connectors, power signaling, and uses, docks are unstandardized and are therefore often designed for a specific type of device.
USB On-The-Go is a specification first used in late 2001 that allows USB devices, such as tablets or smartphones, to also act as a host, allowing other USB devices, such as USB flash drives, digital cameras, mouse or keyboards, to be attached to them. Use of USB OTG allows devices to switch back and forth between the roles of host and device. For example, a smartphone may read from removable media as the host device, but present itself as a USB Mass Storage Device when connected to a host computer.
DisplayPort (DP) is a proprietary digital display interface developed by a consortium of PC and chip manufacturers and standardized by the Video Electronics Standards Association (VESA). It is primarily used to connect a video source to a display device such as a computer monitor. It can also carry audio, USB, and other forms of data.
The PS/2 port is a 6-pin mini-DIN connector used for connecting keyboards and mice to a PC compatible computer system. Its name comes from the IBM Personal System/2 series of personal computers, with which it was introduced in 1987. The PS/2 mouse connector generally replaced the older DE-9 RS-232 "serial mouse" connector, while the PS/2 keyboard connector replaced the larger 5-pin/180° DIN connector used in the IBM PC/AT design. The PS/2 keyboard port is electrically and logically identical to the IBM AT keyboard port, differing only in the type of electrical connector used. The PS/2 platform introduced a second port with the same design as the keyboard port for use to connect a mouse; thus the PS/2-style keyboard and mouse interfaces are electrically similar and employ the same communication protocol. However, unlike the otherwise similar Apple Desktop Bus connector used by Apple, a given system's keyboard and mouse port may not be interchangeable since the two devices use different sets of commands and the device drivers generally are hard-coded to communicate with each device at the address of the port that is conventionally assigned to that device.
A computer port is a hardware piece on a computer where an electrical connector can be plugged to link the device to external devices, such as another computer, a peripheral device or network equipment.This is a non-standard term.
PoweredUSB, also known as Retail USB, USB PlusPower, USB +Power, and USB Power Plus, is an addition to the Universal Serial Bus standard that allows for higher-power devices to obtain power through their USB host instead of requiring an independent power supply or external AC adapter. It is mostly used in point-of-sale equipment, such as receipt printers, touch monitor and barcode readers.
Universal Serial Bus 3.0, marketed as SuperSpeed USB, is the third major version of the Universal Serial Bus (USB) standard for interfacing computers and electronic devices. It was released in November 2008. The USB 3.0 specification defined a new architecture and protocol, named SuperSpeed, which included a new lane for providing full-duplex data transfers that physically required five additional wires and pins, while also adding a new signal coding scheme, and preserving the USB 2.0 architecture and protocols and therefore keeping the original four pins and wires for the USB 2.0 backward-compatibility, resulting in nine wires in total and nine or ten pins at connector interfaces. The new transfer rate, marketed as SuperSpeed USB (SS), can transfer signals at up to 5 Gbit/s with raw data rate of 500 MB/s after encoding overhead, which is about 10 times faster than High-Speed. USB 3.0 Type-A and B connectors are usually blue, to distinguish them from USB 2.0 connectors, as recommended by the specification, and by the initials SS.
Thunderbolt is the brand name of a hardware interface for the connection of external peripherals to a computer. It was developed by Intel in collaboration with Apple. It was initially marketed under the name Light Peak, and first sold as part of an end-user product on 24 February 2011.
IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony and Panasonic. It is most commonly known by the name FireWire (Apple), though other brand names exist such as i.LINK (Sony), and Lynx.
In computing, ‘’‘eSATAp’’’ is a combination connection for external storage devices. This type of port allows for either an eSATA or USB device to be connected. The eSATAp socket includes keyed cutouts for both types of connectors, ensuring that devices can only be plugged in the correct orientation for compatibility and functionality.
The eXtensible Host Controller Interface (xHCI) is a technical specification that provides a detailed framework for the functioning of a computer's host controller for Universal Serial Bus (USB). Known alternately as the USB 3.0 host controller specification, xHCI is designed to be backward compatible, supporting a wide range of USB devices from older USB 1.x to the more recent USB 3.x versions.
USB-C, or USB Type-C, is a 24-pin connector that supersedes previous USB connectors and can carry audio, video, and other data, to connect to monitors or external drives. It can also provide and receive power, to power, e.g., a laptop or a mobile phone. It is used not only by USB technology, but also by other protocols, including Thunderbolt, PCIe, HDMI, DisplayPort, and others. It is extensible to support future protocols.
The initial versions of the USB standard specified connectors that were easy to use and that would have acceptable life spans; revisions of the standard added smaller connectors useful for compact portable devices. Higher-speed development of the USB standard gave rise to another family of connectors to permit additional data paths. All versions of USB specify cable properties; version 3.x cables include additional data paths. The USB standard included power supply to peripheral devices; modern versions of the standard extend the power delivery limits for battery charging and devices requiring up to 240 watts. USB has been selected as the standard charging format for many mobile phones, reducing the proliferation of proprietary chargers.
This article provides information about the communications aspects of Universal Serial Bus (USB): Signaling, Protocols, Transactions. USB is an industry-standard used to specify cables, connectors, and protocols that are used for communication between electronic devices. USB ports and cables are used to connect hardware such as printers, scanners, keyboards, mice, flash drives, external hard drives, joysticks, cameras, monitors, and more to computers of all kinds. USB also supports signaling rates from 1.5 Mbit/s to 80 Gbit/s depending on the version of the standard. The article explains how USB devices transmit and receive data using electrical signals over the physical layer, how they identify themselves and negotiate parameters such as speed and power with the host or other devices using standard protocols such as USB Device Framework and USB Power Delivery, and how they exchange data using packets of different types and formats such as token, data, handshake, and special packets.
Universal Serial Bus 4 (USB4), sometimes erroneously referred to as USB 4.0, is the most recent technical specification of the USB data communication standard. The USB Implementers Forum originally announced USB4 in 2019.
