VirtualLink was a proposed USB-C alternate mode that was historically intended to allow the power, video, and data required to power

virtual reality headset A virtual reality headset (or VR headset) is a head-mounted device that provides virtual reality for the wearer. VR headsets are widely used with VR video games but they are also used in other applications, including simulators and trainers. VR ...

s to be delivered over a single USB-C cable and connector instead of set of three different cables as it was in older headsets. The standard was supported by

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AMD Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufact ...

HTC Vive VIVE, sometimes referred to as HTC Vive, is a virtual reality brand of HTC Corporation. It consists of hardware like its titular virtual reality headsets and accessories, virtual reality software and services, and initiatives that promote ...

Oculus VR Reality Labs is a business of Meta Platforms (formerly Facebook Inc.) that produces virtual reality (VR) and augmented reality (AR) hardware and software, including virtual reality headsets such as Quest, and online platforms such as Horizon W ...

Valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...

, and

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. The VirtualLink Consortium was chaired by Rambo Jacoby representing Nvidia. VirtualLink never launched successfully.

VirtualLink specifications

According to its specifications, the VirtualLink cable consisted of: *

DisplayPort DisplayPort (DP) is a 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 su ...

: ** 4x DisplayPort balanced pair data path ** DisplayPort HPD (hot-plug detection pin) as a single wire. ** DisplayPort AUX signal as a balanced pair *

USB 3.1 USB 3.0, released in November 2008, is the third major version of the Universal Serial Bus (USB) standard for interfacing computers and electronic devices. Among other improvements, USB 3.0 adds the new transfer rate referred to as '' ...

signals ** A USB TX balanced pair for USB 3.0 data ** A USB RX balanced pair for USB 3.0 data * I2C wire to control the USB Billboard interface, in case the cable is plugged into an unsupported interface. * VBUS carrying power to HMD visor * GND ground The

USB-C USB-C (properly known as USB Type-C) is a 24-pin USB connector system with a rotationally symmetrical connector. The designation C refers only to the connector's physical configuration or form factor and should not be confused with the conne ...

plug pinout specified: Unlike most alt-modes this remapped A7, A6, B6, B7 to carry a USB 3.0 signal, instead of the usual passive USB 2.0 signal. This means that one would not be able to extend the cable using a standard USB-C 3.0 cable, which has these pins mapped only for unshielded USB 2.0 signals. Also this required the VirtualLink port to also detect the correct orientation of the USB-C plug to ensure that the USB 3.0 TX and RX lanes are correctly connected. In VirtualLink mode, there were six high-speed lanes active in the USB-C connector and cable: four lanes transmit four

HBR 3 video streams from the PC to the headset while two lanes implement a bidirectional USB 3.1 Gen 2 channel between the PC and the headset. Unlike the classic DisplayPort USB-C alternate mode, VirtualLink has no USB 2.0 channels active, instead providing a higher speed USB 3.1 Gen 2 (SuperSpeed+) over the same A6, A7, B7, B6 pins. VirtualLink also required the PC to provide 15 to 27 watts of power. No information pertaining to VirtualLink alternate mode compatibility with

USB4 USB4 (aka: USB 4.0) is a specification by the USB Implementers Forum (USB-IF), which was released in version 1.0 on 29 August 2019. The USB4 protocol is based on the Thunderbolt 3 protocol; the Thunderbolt 3 specification was donated to the US ...

(and so Thunderbolt 3 alternate mode) had been published. To achieve six high-speed lanes over USB-C, VirtualLink required special cables that conformed to version 1.3 of the USB-C standard and used shielded differential pairs for both USB 2.0 pairs. The available bandwidth was estimated to be equivalent to DisplayPort 1.4 (32.4 Gbit/s, up to 4K @ 120 Hz with 8 bpc color) for video and 10 Gbit/s of USB 3.1 Gen 2 data.

Implementation in graphics cards and devices

GeForce 20 series The GeForce 20 series is a family of graphics processing units developed by Nvidia. Serving as the successor to the GeForce 10 series, the line started shipping on September 20, 2018, and after several editions, on July 2, 2019, the GeForce RT ...

cards, initially released in 2018, implemented a single VirtualLink port in all RTX Founders Edition (FE) cards (2060, 2070, 2080, 2080 Ti). This port was also made available on Quadro RTX cards. As of Nvidia's

GeForce 30 series The GeForce 30 series is a suite of graphics processing units (GPUs) designed and marketed by Nvidia, succeeding the GeForce 20 series. The GeForce 30 series is based on the Ampere architecture, which feature Nvidia's second-generation ray t ...

cards announcement, all of Nvidia's new Founders Edition GPUs, alongside the partner boards announced so far, lacked a VirtualLink port due to its discontinuation. By contrast, the AMD

Radeon RX 6000 series The Radeon RX 6000 series is a series of graphics processing units developed by AMD, based on their RDNA 2 architecture. It was announced on October 28, 2020 and is the successor to the Radeon RX 5000 series. It consists of the RX 6400, RX 65 ...

, announced in October 2020, implemented a VirtualLink port for the first time.

Discontinuation & abandonment

As of August 2020, the VirtualLink standard had failed to propagate into the virtual reality headset market. The Valve Index had initially developed a VirtualLink accessory, but it was canceled due to technical signaling and reliability issues. By September of that year, it had been abandoned by its consortium, and the website now redirects to its

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page.

References

{{Reflist, 2

External links

VirtualLink Consortium website
*http://www.virtuallink.org/ USB Virtual reality headsets Defunct technology companies