Home Technology USB Implementers Forum publishes USB4 specification, adding to USB-C…onfusion

USB Implementers Forum publishes USB4 specification, adding to USB-C…onfusion

2 min read

I’m still waiting for the world to adopt USB 3 properly, especially the USB-C type cable that usually accompanies it. As a standard, USB has become anything but, with different branching standards and nomenclatures that only confuse consumers more. I think XKCD summed up industry “standards” best.


Anyway, the USB Implementers Forum, the non-profit that presides over the USB standard has now published the USB4 specification, and if you were hoping that it would make things clearer and easier for the general populace, well then I don’t know what to tell ya’ buddy.

It’ll build on the existing standard (which means back-compatibility) and also effectively swallow up the thunderbolt spec too. According to the USB-IF, the key characteristics include the following:

  • Two-lane operation using existing USB Type-C cables and up to 40Gbps operation over 40Gbps certified cables
  • Multiple data and display protocols that efficiently share the maximum aggregate bandwidth
  • Backward compatibility with USB 3.2, USB 2.0 and Thunderbolt 3

“As the USB Type-C connector has evolved into the role as the external display port of many host products, the USB4 specification provides the host the ability to optimally scale allocations for display data flow. Even as the USB4 specification introduces a new underlying protocol, compatibility with existing USB 3.2, USB 2.0 and Thunderbolt 3 hosts and devices is supported; the resulting connection scales to the best mutual capability of the devices being connected”

Okay then. Unfortunately, it seems as if the USB4 (no space!) standard will have a few confusing names of its own, with different “grades” USB4 depending on the cable and application. If you can recall, the latest USB 3 standard has silly names like “USB 3.2 Gen 2×2” and that seems set to continue.

“Once the specifications are released, there will be a new round of confusion,” a source familiar with the spec told TechRepublic. “It’s going to be USB4, but you have to qualify what USB4 means, because there are different grades. USB4, by definition, has to be [at least] Gen 2×2, so it will give you 10 Gbps by 2, that’s 20 Gbps. There’s going to be USB4 Gen 3×2, which is 20 Gbps per lane. 20 by 2 will give you 40 Gbps.”

Oh lord. USB4 devices should start appearing next year, at which time manufacturers will start embracing USB 3.

Last Updated: September 4, 2019

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