The New USB4 Spec: Faster Speeds, Optimized Video Transfer, and Thunderbolt 3 Compatibility

USB4 Connector Original photo: Tony Webster

There has been a lot of buzz with USB lately – with all the new specifications being released and even the rebranding of the latest USB 3.x specifications, it seems there are new USB updates coming out left and right. Now, USB-IF has introduced an even newer specification to add to the mix: USB4.

What are USB4 Key Features?

What is the newest USB4 specification and how does it different from previous releases? The new upcoming spec was only recently announced by the USB Promoter Group. The USB Promoter Group has only released its roadmap to USB4, so no definite USB4 specifications have been released thus far. The most prevalent updates include increased data transfer rates, compatibility with Thunderbolt 3 devices, and enhanced resource allocation for video.

USB4 connects with Thunderbolt 3 Technology Photo by Maurizio Pesce

USB4 and Thunderbolt 3 Technology

Thunderbolt 3, created by Intel, introduces a technology that governs some of the most advanced data transfer rates, power charging, and video display capabilities all in one cable – intended to be the cable of all cables. Recently, Intel made the move to release the Thunderbolt 3 technology to the industry where manufacturers could now use this standard royalty free, allowing USB4 to become an open standard across multiple devices. By combining USB and Thunderbolt 3, this will allow interoperability between the two and create an overall standardization of ports, cabling, and protocols.

As per usual, USB4 will build upon and provide backwards compatibility with the preceding USB 3.2 and USB 2.0 architectures. However, one of the major differences USB4 has compared to previous USB specs is its compatibility with Thunderbolt technology, specifically Thunderbolt 3. Because USB4 uses the Thunderbolt 3 standard as its foundation, there are many comparable features between the two. Like Thunderbolt 3, USB4 will continue to utilize USB Type-C as its connector type, benefiting from its high-performance capabilities.

A Blend of Faster Speeds and Enhanced Video Display

USB4 will also match the incredibly fast data transfer speeds of Thunderbolt 3 with 40 Gbps - twice that of the preceding USB 3.2 2x2 spec, by using a two-lane operation of up to 20 Gbps each. It will also continue to comply with the advanced Power Delivery protocol, allowing for higher wattages and better power management, supporting fast charging with up to 100W of power.

The Type-C connector has allowed cables to become capable of transferring not only data, but video protocols as well. The USB4 spec will optimize the blend of data and display over a single connection by having them share the total available bandwidth over the bus, allowing the support for two 4K display connections or a single 5K display.

The USB Operator Group mentioned in their latest statement regarding USB4, “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.”

The official USB4 specification has not been released, so all details on features concerning Thunderbolt 3 with USB4 are still to come.

How Total Phase Can Support your USB Application

Total Phase offers a variety of debugging and development tools for USB. We offer an extensive line of USB protocol analyzers for USB 2.0/USB 3.1 Gen 1 specs, all being able to non-intrusively monitor and debug USB data on the bus in real time. For Type-C specifically, the USB Power Delivery Analyzer allows users to capture and debug PD negotiation occurring on the CC1 and CC2 lines without disturbing USB data, and supports the latest PD 3.0 spec and offers DisplayPort VDM decoding. Our Advanced Cable Tester v2 also provides a comprehensive testing tool that measures the safety and quality of cables, supports a variety of USB and video cables. It supports signal integrity testing of cables up to 12.8 Gbps per line, supporting the latest USB 3.2 Gen 2x2 spec and HDMI 2.1.

For more information on how Total Phase can help with your USB application, please contact us. You can also request a demo that applies to your application.