VirtualLink


VirtualLink is a proposed USB-C alternate mode that allows the power, video, and data required to power virtual reality headsets 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 is supported by Nvidia, AMD, HTC Vive, Oculus VR, Valve, and Microsoft. The VirtualLink Consortium is chaired by Rambod Jacoby representing NVIDIA.
In VirtualLink mode there are six high-speed lanes active in the USB-C connector and cable: 4 lanes transmit four DisplayPort HBR 3 video streams from the PC to the headset while two lanes implement 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 over the same A6, A7, B7, B6 pins. VirtualLink also requires the PC to provide 15 to 27 Watts of power. No information pertaining to VirtualLink alternate mode compatibility with USB4 has been published, as of April 2019.
To achieve 6 high-speed lanes over USB-C, VirtualLink requires special cables that conform to version 1.3 of the USB-C standard and uses shielded differential pairs for both USB 2.0 pairs.
The available bandwidth is estimated to be equivalent to DisplayPort 1.4 for video and 10 Gbit/s of USB 3.1 Gen 2 data.
Nvidia GeForce 20 series cards, initially released in 2018, implement a single VirtualLink port in all RTX Founders Edition cards. This port is also available on Quadro RTX cards.

VirtualLink cable

The virtuallink cable consists of
The USB-C plugs pinout is :
A12A11A10A9A8A7A6A5A4A3A2A1
GNDDP+DP−VCC1USBTX+USBTX−DP+VDP−DP+GND
GNDDP+DP−VDP-USBRX−USBRX+VCONNVDP−DP+GND
B1B2B3B4B5B6B7B8B9B10B11B12

Unlike most alt-mode; this will also remap A7, A6, B6, B7 to carry USB 3.0 signal, instead of the usual passive USB 2.0 signal. This means that one will 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 will require 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.