USB

USB (Universal Serial Bus) is an industry standard for cables, connectors, and protocols that connect, communicate with, and supply power to electronic devices. It was developed in the mid-1990s by a group of companies led by Intel to replace the separate serial, parallel, PS/2, and game ports then used for keyboards, mice, printers, and other peripherals with a single plug-and-play interface. The standard is maintained by the USB Implementers Forum (USB-IF), a non-profit organization that owns the trademarks and runs the compliance program.

In virtual reality and augmented reality, USB carries the data, video, and power that connect headsets to host computers and peripherals. A USB cable links a Meta Quest standalone headset to a PC for tethered play, the reversible USB-C connector and its DisplayPort Alt Mode allow a single cable to feed video to some headsets, and USB Power Delivery charges headsets and controllers. A dedicated VR-focused variant, VirtualLink, was proposed in 2018 to combine all of these over one USB-C cable but was abandoned by 2020.

Origin and development

The work that became USB began at Intel in the early 1990s. Engineer Ajay Bhatt pushed for a universal plug-and-play connector after struggling to install a printer, and after an initial rejection he joined a research group that approved the project. In 1994 a meeting at Intel's Jones Farm Conference Center in Hillsboro, Oregon brought together engineers from several companies to form an alliance, and a first design was announced in 1995. Seven companies collaborated on the early specification: Compaq, Digital Equipment Corporation (DEC), IBM, Intel, Microsoft, NEC, and Nortel.

USB 1.0 was released in January 1996 with two signaling rates: 1.5 Mbit/s (Low Speed) for inexpensive devices on unshielded cables and 12 Mbit/s (Full Speed). Adoption was slow until 1998, when Microsoft Windows 98 shipped with USB support and Apple released the iMac, which dropped legacy ports in favor of USB. USB 1.1, a clarified revision, followed in 1998.

Version history

Successive USB generations have raised data rates by roughly an order of magnitude each. The branding has been revised repeatedly: the 5 Gbit/s tier introduced as USB 3.0 was later renamed USB 3.1 Gen 1 and then USB 3.2 Gen 1, which has caused confusion between specification names and the marketing names used on products.

Specification	Year	Maximum data rate	Common marketing name
USB 1.0	1996	1.5 / 12 Mbit/s	Low Speed / Full Speed
USB 2.0	2000	480 Mbit/s	Hi-Speed
USB 3.0 (later 3.1 Gen 1, 3.2 Gen 1)	2008	5 Gbit/s	SuperSpeed USB 5Gbps
USB 3.1 Gen 2 (later 3.2 Gen 2)	2013	10 Gbit/s	SuperSpeed USB 10Gbps
USB 3.2 Gen 2x2	2017	20 Gbit/s	SuperSpeed USB 20Gbps
USB4	2019	40 Gbit/s	USB4 40Gbps
USB4 Version 2.0	2022	80 Gbit/s	USB4 80Gbps

USB 2.0, published in 2000, raised the ceiling to 480 Mbit/s. USB 3.0, published in 2008, added a 5 Gbit/s "SuperSpeed" mode using additional wires alongside the original USB 2.0 pins. USB 3.1 (2013) introduced a 10 Gbit/s tier, and USB 3.2 (2017) added a 20 Gbit/s tier (Gen 2x2) by running two 10 Gbit/s lanes over the USB-C connector.

USB4, published in 2019, requires the USB-C connector, reaches 40 Gbit/s, and is built on the Thunderbolt 3 protocol that Intel contributed to the USB Promoter Group; it is backward compatible with earlier USB versions and with Thunderbolt 3.

USB-IF published USB4 Version 2.0, branded USB 80Gbps, on October 18, 2022. It doubles the aggregate bandwidth to 80 Gbit/s (two lanes of 40 Gbit/s in each direction) and is the first USB standard to use PAM3 (three-level) signaling at 25.6 Gbaud. For demanding uses such as driving high-resolution displays, the link can be configured asymmetrically to deliver up to 120 Gbit/s in one direction while retaining 40 Gbit/s in the other. It remains backward compatible with earlier USB versions and with Thunderbolt 3.

Connectors

USB has used several physical connectors. The original rectangular Type-A plug and the square-ish Type-B plug were joined by Mini and Micro variants for smaller devices. The USB-C connector, published by USB-IF on August 11, 2014 alongside USB 3.1, is a 24-pin reversible plug that supersedes the earlier connectors and carries power, data, and video. USB4 mandates the USB-C connector. The connector type is independent of the data rate: a USB-C port may run anything from USB 2.0 speeds to 80 Gbit/s depending on the host and cable, which is why the speed a given VR cable supports cannot be inferred from its plug shape alone.

USB-C also carries non-USB data through Alternate Modes, in which some of the connector's high-speed lanes are repurposed for another protocol. DisplayPort Alt Mode, which routes a DisplayPort video signal over the USB-C pins, is the mode most relevant to VR because it lets a single USB-C cable deliver headset video.

Power delivery

Basic USB ports supply limited power (for example 2.5 W over USB 2.0 and 4.5 W over USB 3.0 at 5 V). USB Power Delivery (USB PD) negotiates higher voltages and currents over USB-C. The original USB PD allowed up to 100 W (20 V at 5 A). Revision 3.1, announced in 2021, added an Extended Power Range (EPR) with new 28 V, 36 V, and 48 V fixed voltages, enabling up to 240 W (48 V at 5 A) over an electronically marked (e-marked) cable rated for the higher current. USB PD is what lets a single cable both run a tethered headset and charge it, and it powers the chargers used for standalone headsets and controllers.

Use in VR and AR

USB is central to how VR and AR hardware connects, in several distinct roles.

Tethered PC connection

Standalone headsets can run PC VR content by tethering to a computer over USB. Meta's wired link feature, originally Oculus Link and now branded Meta Horizon Link, streams a compressed rendered image from a PC to a Meta Quest headset over a USB cable. Meta specifies a USB-C 3.2 cable supporting at least 5 Gbit/s, plugged into a USB 3.0 port on the PC. When Link launched in 2019 it required a USB 3.0 connection, but Meta later relaxed the official requirement so that even the USB 2.0 charging cable bundled with the headset can work, at lower bandwidth than a USB 3.0 cable allows. Because the image is compressed and sent over the cable, the usable bandwidth affects visual quality. A wireless alternative, Air Link, runs the same stream over Wi-Fi instead of USB.

Older PC headsets such as the original Oculus Rift and HTC Vive instead used USB for data and tracking while sending video over a separate HDMI or DisplayPort cable, so a typical setup occupied a USB port plus a video port.

Video over USB-C

DisplayPort Alt Mode lets a USB-C port output a DisplayPort video signal, which some headsets use directly. Headsets that expose a DisplayPort connection, including the Oculus Rift S and the Valve Index, can be driven from a USB-C port that supports DisplayPort Alt Mode through a USB-C to DisplayPort adapter, provided the port is wired to the discrete GPU. Standalone headsets can also output video the other way: Meta added a DisplayPort Alt Mode output to the Meta Quest 3 in the v74 software update, letting the headset mirror its view to an external monitor or TV over a USB-C cable.

VirtualLink

VirtualLink was a USB-C Alternate Mode proposed in July 2018 to carry everything a VR headset needs over one USB-C cable instead of three separate cables. The VirtualLink Consortium was formed by Nvidia, AMD, Oculus VR, Valve, HTC Vive, and Microsoft. The mode combined four lanes of DisplayPort High Bit Rate 3 video, a USB 3.1 Gen 2 (10 Gbit/s) data channel, and 15 to 27 W of power over USB Power Delivery. Nvidia included a single VirtualLink port on its GeForce RTX 20-series Founders Edition graphics cards (the RTX 2060, 2070, 2080, and 2080 Ti, released in 2018), and Quadro RTX cards also carried it. Valve developed a VirtualLink adapter for the Index but canceled it in August 2019, citing technical issues and limited adoption of the port on laptops. By September 2020 the consortium had abandoned the standard, and no major headset shipped using it as its primary connection.

Charging and accessories

USB-C is the charging and accessory port on current standalone headsets and their controllers. Headsets charge over USB-C, and USB Power Delivery sets the rate at which they and battery accessories refill. The same port is used with USB-C to USB-A cables or adapters when a PC lacks a USB-C port.

Developer access and sideloading

A USB connection also gives developers and users low-level access to standalone headsets. With Developer Mode enabled and USB debugging authorized on the headset, a PC connected by a USB cable can use the Android Debug Bridge (ADB) to transfer files, read logs, and install applications outside the official store, a process commonly run through the third-party tool SideQuest. The cable used for this must support data, not power only.

Current status

As of 2026, USB is on every consumer VR and AR headset for charging and data, and USB-C with DisplayPort Alt Mode is the common path for cabled video. USB4 Version 2.0 (USB 80Gbps) is the newest published specification, and its higher bandwidth and asymmetric mode are aimed in part at driving high-resolution displays. The dedicated VR connector VirtualLink did not survive, so headsets rely on general-purpose USB-C, DisplayPort Alt Mode, and USB Power Delivery rather than a VR-specific port.