Clearing Up the Confusion About USB... Again


For something that has universal in its name, USB naming conventions are anything but. From long names to standard changes, it can become increasingly difficult to figure out what all the letters and numbers mean. And it has only gotten worse, now that USB naming conventions have changed once again.

First, we’ll look at the number that follows USB, like USB 3.2 Gen 1, USB 3.1 Gen 1, USB 3.0, and USB 2.0. That number refers to different maximum data-transfer rates. Let’s start with the most confusing one: USB 3.2 Gen 1 can support up to 5 Gb/s. USB 3.1 Gen 1 and USB 3.0 also support up to 5 Gb/s. That’s because they’re all synonymous. The naming conventions for USB 3.0 and USB 3.1 Gen 1 are now USB 3.2 Gen 1, although not all manufacturers have adopted it yet. Some older products will also still be called USB 3.0 or USB 3.1 Gen 1. Please note that USB 3.2 Gen 1, USB 3.1 Gen 1, and USB 3.0 refer to the same speed, not connector (more on that later).

Tera Grand USB 3.2 Gen 1 Type-C to USB Type-A Female Adapter Cable

USB 3.1 Gen 2 is now USB 3.2 Gen 2, and still supports 10 Gb/s. Again, not all manufacturers have adopted this naming convention yet, so don’t fret if you receive a product that says USB 3.1 Gen 2. It’ll still do 10 Gb/s, theoretically.

Tera Grand USB 3.2 Gen 2 Type-C to USB Type-A Braided Cable

There is also a new USB standard with a new maximum data-transfer rate. Most people would think it would be called USB 3.2 Gen 3… right? Well, we hate to be the bearers of bad news, but it isn’t. The new standard is called USB 3.2 Gen 2x2 and it can do 20 Gb/s. Now, before you get out your pitchforks and torches, USB-IF offers an explanation. USB 3.2 Gen 2x2 got its name because it represents multi-lane operation in new USB 3.2 devices. It supports a total of 20 Gb/s, provided by two 10 Gb/s lanes. They were also able to do this without sacrificing cable length.

USB 2.0 can support up to 480 Mb/s, while USB 1.1 can support 12 Mb/s. If they share the same connector type, USB 3.1 Gen 2 and USB 3.1 Gen 1 can be backward-compatible with older devices, although they will be limited to the older USB standard’s data transfer rate.

Here’s a quick little table we’ve made for you:


Data Transfer Rate

USB 3.2 Gen 1 = USB 3.1 Gen 1 = USB 3.0 5 Gb/s
USB 3.2 Gen 2 = USB 3.1 Gen 2 10 Gb/s
USB 3.2 Gen 2x2 20 Gb/s

Now onto the letter that follows, like USB 3.2 Gen 2 Type-C, USB 2.0 Type-A, and more. The letter refers to the connector type. USB Type-A is the most popular connector and port, commonly found on computers. Its rectangular shape requires the connector to be placed in a certain direction (a common mistake we all make). A more recent connector type is USB Type-C. Type-C embraces a slim, reversible oval-shaped connector. The slim design is tailored to fit mobile devices, laptops, and tablets while also allowing reversible plug orientation and cable direction. You’ll notice that Thunderbolt™ 3 utilizes the USB Type-C connector. Thunderbolt™ 3 supports a maximum data-transfer rate of 40 Gb/s and it will also support USB 3.2 Gen 2 at 10 Gb/s. The device must state that it supports Thunderbolt™ 3. If the device is only stated to be USB 3.2 Gen 2, it cannot support the 40 Gb/s of Thunderbolt™ 3, and will be limited to its native 10 Gb/s.

Comprehensive USB 3.2 Gen 2 Type-C Cable with Power Delivery

USB Type-B is not as common as the previously mentioned connector types, but the square-like connector lives on, usually in printers. While some Android mobile devices have moved over to the USB Type-C connector, there are some older smartphones and tablets that still use the USB micro-B connector.

C2G Panel-Mount USB 2.0 Type-B Female to USB 2.0 Type B Male Cable

So, as a refresher, the number after USB refers to the data transfer rate and the letter after that refers to the connector type. For example, USB 3.2 Gen 1 Type-A and USB 3.0 Type-A are identical, but USB 3.2 Gen 1 Type-C and USB 3.0 Type-A are not (both support 5 Gb/s, but have different connectors). Hopefully, this short guide will help you navigate the confusing world of USB. You can put your newly acquired USB knowledge to the test by using our handy cable finder to find the right USB cable for your computer.


I have a Macbook Pro with two USB ports, an HDMI port and a SD card slot.  I also have two thunderbolt 400 ports which are basically worthless as no contemporary devices have these connectors.  What adapter options are there to take advantage of these ports.  Thanks, KT

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