image PNG Image, 593 × 390 pixels.png

What is MTT?

https://discord.com/channels/849300336128032789/1146536041763831948

Vive Tracker dongles are pretty simple devices - they have a small wireless chip inside them that's connected to the USB port. That chip is a dated one and uses a very old USB version that sends data at a low rate (the dongle doesn't need more than that anyway).

But there are USB hubs that will slow down the whole big USB line to the lowest speed because of one single dongle - and the hub you already have may be one of those STT ones.

Thankfully there are hubs that don't do that with a clever trick called MTT. The sad part is that most USB hub descriptions don't have any mentions of the MTT mode, and Windows doesn't outright tell you if your hub is a better one.

Why does this help improve tracking?

Multi-TT hub can improve performance for Vive dongles—even though they’re nominally “USB 2.0” devices—because they typically operate at full-speed (12 Mbps) and thus rely on a transaction translator within the hub. Having a Multi-TT design helps avoid bandwidth/latency bottlenecks if you’re running lots of dongle off a since USB hub.

Does MTT only matter for USB 1.1 devices?

<aside> 🖱️

Multi-TT (Multiple Transaction Translators) only applies to USB 1.1 devices (1.5 Mbps low-speed and 12 Mbps full-speed), not USB 2.0 devices.

Single-TT vs. Multi-TT

  1. Single-TT Hub

Multi-TT Hub

Source: https://web.archive.org/web/20140202123914/http://www.tomshardware.com/reviews/usb-technology,677-3.html

Finding out if your hub is an STT or MTT one

The slow way to check the hub is to open the Device Manager tool, find the hub there and open its properties - one of the tabs will tell you that the hub has multiple transaction transmitters - that's what MTT means.

The quicker way is through a tool called USB Device Tree Viewer