In March 2019 the USB Promoter Group announced the USB4 specification. Apart from the the lack of a space between the B and the 4, the thing we noticed was a predictable and, given the history of USB we might even say inevitable, convergence between standards which looks like it will make things easier and simpler for all of us.

USB-C Fast, But Not Universal

The direction of travel for the USB standard is of course upwards in terms of transfer speeds, and dramatically so. What started out as a replacement for parallel ports and PS/2 ports is now vastly faster but it still isn’t quite universal, which is a pity considering what the U in USB stands for. Firewire is pretty much consigned to history, but as USB is now so fast it offers an attractive alternative to Thunderbolt, with similar transfer rates at a lower cost. The case for convergence is obvious and USB-C connectors have offered a way of combining the two in a single hardware layer. However, you ay not be aware that not all USB-C cables carry Thunderbolt and users don’t want, and shouldn’t need to, have to work out the difference, they just want to be able to plug things together and get blistering performance. Can we get that?

USB4 - Properly Universal Interconnection?

USB 3 offers 20Gb/s transfer speeds with retrospective compatibility with legacy USB peripherals. USB-C offers small and reversible connectors and the ability to carry Thunderbolt connections. Given this level of convergence the logical next step is for the distinction between Thunderbolt and USB connections to become transparent to the user. The licensing requirements imposed on Thunderbolt peripherals, which formed a historical barrier to this happening were lifted last year when Intel waived these requirements. This made the development of Thunderbolt peripherals similar to USB in terms of licensing and cost.

Thunderbolt is owned by Intel and although it is now available licence free, to use Thunderbolt still requires working with Intel to pass compatibility testing, a requirement which doesn’t exist with USB devices. Also USB-C cables are not all capable of carrying Thunderbolt, creating a confusing, two tier arrangement.

What Is The Point Of USB4?

Brad Saunders, USB Promoter Group Chairman put it this way…

“The primary goal of USB is to deliver the best user experience combining data, display and power delivery over a user-friendly and robust cable and connector solution, The USB4 solution specifically tailors bus operation to further enhance this experience by optimizing the blend of data and display over a single connection and enabling the further doubling of performance.”

What this means in practice is that the the connection scales to the best mutual capability of the devices being connected. USB4 introduces Thunderbolt compatibility with existing USB 3.2, USB 2.0 and with the added simplicity it means that the available bandwidth can be deployed efficiently without breaking compatibility with USB or Thunderbolt devices.

USB4 Specs At A Glance

• Up to 40GB/s

• Thunderbolt 3 Compatibility

• USB 3.1 Gen 2 Compatibility

• USB 2.0

• 100W Charging Power/15W Bus Power

• Video Bandwidth for 2x 4K displays

• Thunderbolt 3 compatible USB-C cables

USB4 kind of feels a bit “so what, big deal!”. It’s faster, simpler and doesn’t break my old stuff. And that is precisely what a new connection protocol should be. Easier isn’t exciting, but it’s definitely good. However there is a potential issue in that while Thunderbolt is part of the spec, it isn’t a required part of the spec. because of this, and the costs of getting Intel certification to use Thunderbolt it is quite likely that the very cheapest brands will market USB4 gear which isn’t Thunderbolt… Sounds familiar?

What about Apple?

Apple being Apple are likely to be early adopters but exactly when they release Apple computers with USB4 isn’t something we can predict. One thing which it will definitely bring into focus is the future of the lightning connector on iOS devices. The iPad Pro already has a USB-C connector which doesn’t support Thunderbolt. Will that change?

What Does USB 4 Mean For Audio Users?

Simplicity - Convergence onto one cable type for more peripherals, and a reversible connector - why does it take three attempts to plug in a USB cable?

Speed and availability - Doubling of the data rate for Thunderbolt. If the bottleneck on your system is disk speed then Thunderbolt offers a solution and converging Thunderbolt with USB should drive up adoption by hardware manufacturers. Thunderbolt should become more attractive to PC manufacturers, particularly at the less expensive end of the market. An additional driver for this is Intel’s decision in 2017 to make Thunderbolt royalty free.

Of course USB4 may be coming but it isn’t here yet, USB4 is expected to launch in the middle of 2019 but it will 2020 before we see any hardware and it could be 2 years before we see USB4 PC laptops becoming commonplace. Will USB4 help your workflow?