(201303, 201323, 201503) USB4 20Gbps vs. USB 3.2 Gen2x2: Addressing Interpretation Discrepancies in USB Standard Readings

Cable Matters has launched an investigation to resolve customer concerns regarding our USB4 20Gbps cables, particularly based on feedback that some utilities are identifying them as USB 3.2 Gen2 cables.

We take customer feedback seriously and are dedicated to solving any concerns. Below we will publish a comprehensive report based on the findings of our Research & Development Team and Engineers. 

Applies To:

This guide applies to Cable Matters USB4 20Gbps Cables. 

This guide applies to the following products:

• [USB-IF Certified] Cable Matters USB4 Cable 6 ft with 20Gbps Data, 8K Video Support, and 100W Charging (201303)
• USB4 20Gbps Cable in Black (201323)
• [Designed for Surface] USB4 Cable 6 ft Supporting 20Gbps Data, 8K Video, and 100W Charging (201503)

General Information:

This report addresses customer feedback regarding the interpretation of some devices' USB standards. Customers noted that utilities identified our USB4 20Gbps cables as USB 3.2 Gen2 cables.

To address this confusion and validate our products' technical specifications, we have conducted a comprehensive investigation.

For our investigation, we used the Cypress tool and TotalPhase analyzer, industry-leading solutions in USB protocol analysis. We also verified USB4 compliance through consultation with our vendor's technical documentation and testing results.

The results from both our vendor and our testing tools align with each other, confirming that our cables can support USB4 Gen2.

Here's a summary of the latest USB Type-C Specification (October 2023 Revision 2.3), where they indicate that Passive USB4 Gen2 20Gbps Cables will indicate support for USB 3.2 Gen2 (010b). 

Results:

Our test results confirmed that our products displayed the cable speed as [USB 3.2/USB4 Gen2].

According to the USB Power Delivery version 3.0 (PD3.0) specifications, the binary sequence '010b' corresponds to USB 3.2 Gen2 or USB4 Gen2 SuperSpeed+.

Their USB signaling is written as 010b, and we have used tools to confirm these bits in our tests (both Cypress tool and TotalPhase can read it). 

The phenomenon of some utility tools reading USB4 Gen2 cables as USB 3.2 Gen2 is a recognized limitation related to certain detection tools, or certain testing environments, not the cable's capabilities.

Below is an image of how we used our Cypress tool to read the binary bit of USB signaling in the E-Marker of the cable to see if it is 010, as USB3.2 Gen2 and USB4 Gen2 for USB signaling in the PD3.0 protocol should be 010.

As indicated, the value is 010, which means our product supports USB4 Gen2 as listed and advertised.

Owing to backward compatibility, USB 3.2 Gen2 and USB4 may be interlaced in some interfaces, leading to the display of an older standard. USB4 introduces a new optional capability, but the primary data transport remains the same as USB 3.2.

Conclusion:

Our investigation conclusively verifies that our product supports USB4 Gen 2. However, some tools and devices may only display this as USB 3.2 Gen2, the older protocol.

This is because not all tools or device drivers have been updated to discern the newest USB protocols, it does not diminish the cable's actual capabilities.

The results from our evaluations offer a definitive resolution to the stated concerns and underscore our commitment to providing accurate, transparent product information. We will use these results to provide clearer product descriptions, updated usage instructions, and improved customer communication.

We remain dedicated to offering reliable and high-standard products and appreciate our customers for highlighting an area we can improve to ensure a comprehensive understanding of our products.