Steam Link's Wired Beta Works Because Horizon OS Turned the USB Port Into a Network Adapter

NCM is a USB device class, short for Network Control Model, and it is the reason a cable you have been charging your Quest with can now carry a PC VR stream. Flip the headset's USB port into NCM mode and it stops being a charging and file transfer connection. It becomes a plain network interface instead. Windows sees a new adapter. Android sees a wired network. Neither end cares that the wire happens to be USB.

Meta switched that capability on in Horizon OS 2.5. Meta's Android apps documentation covers USB networking support, and describes an app requesting a direct network link to a connected host computer once you approve the system-wide permission. The plumbing sat there for months with little using it. This week Valve started using it.

What the beta does

The current public beta of Steam Link on Quest streams over the cable. You launch the app first, then plug in a data-capable USB-C cable, and the SteamVR dock signals an active USB connection with a cycling Wi-Fi icon. UploadVR reported the change on September 2. Virtual Desktop beat it there by about a month.

Opting in takes three separate steps, and none of them sit anywhere obvious. You join the Steam Link for Meta Quest public beta channel through Valve's invite link, signed in with the Meta account your headset uses. On the PC you opt into the SteamVR beta, and then, separately, into the Steam client beta, which is the actual prerequisite for wired streaming without Wi-Fi. Valve has not published a cable spec for any of this. Road to VR suggests borrowing Meta's Link cable guidance: USB 3.0 or better, and long enough that you are not pinned to the desk.

Wi-Fi still has to be on

The feature is not finished. In UploadVR's testing the app would not find the host PC with Wi-Fi disabled, and appeared to want the PC discovered over the wireless network before it would move the stream onto the cable. Which is not really what wired mode is supposed to mean. Treat the current release as a first pass.

A very small repo already mapped the terrain

Before Valve shipped anything, somebody did this by hand. Wired Steam Link VR is an MIT-licensed PowerShell script that flips the headset into NCM mode over adb, runs a DHCP server on the Windows side so the headset's waiting DHCP client actually gets an address, and lets Steam Link connect across the resulting interface. It is tiny. One maintainer, seven commits, one star, and a README that says it has been tested on exactly one Quest 2 running Android 14 and should be treated as beta until more people run it.

The value is in the failure notes. RNDIS, the older USB networking mode most guides still recommend, is not exposed by this hardware at all. Android's tethering service cannot claim the interface either, because the build ships an empty list of tetherable NCM devices, so the error it writes to logcat sends you chasing the wrong thing. Then the real catch: Android only prefers a cable over Wi-Fi once that connection validates, and validating requires real internet behind it. So the project also runs NAT, address translation that shares the PC's own connection down the wire. That fits the behavior Valve's beta is showing, though nobody outside Valve can confirm it.

The measurements are useful too. On a Quest 2 with a USB 3 cable in a USB 3 port, the project logged a 0.7 ms round trip and around 756 Mbit/s, capped by headset storage rather than by the link. One finding will save somebody an evening. Any active VpnService on the headset silently swallows the connection while every status check keeps reporting success.

Why a cable, in 2026

A good Wi-Fi 6E router is fine for most people, and plenty of Quest owners never touch PC streaming. The argument for the wire is the tail end of the distribution. A cable does not contend with a neighbor's network, does not renegotiate mid-session, and holds its bitrate when the room fills with other radios. That matters more as the ceiling rises. Meta only just opened extended refresh rates up to 240 Hz on Quest 3, and those frames still have to travel from somewhere. Anyone running flat PC games through VR mods is already pushing that kind of load.

None of this is ready for everyone. It is a beta channel stacked on two other beta channels, and the headline capability does not fully work. But the platform piece underneath it is real and documented. These will not be the last two apps to reach for it.