Understand USB in 3 minutes

Recently, many friends have asked me about the USB interface, and many of them have very serious misunderstandings.For example: think that USB3.2 must be better than USB 3.1, and USB 3.1 must be better than USB 3.0, or USB Type-C interface must be faster than USB Type-A interface.Speaking of it, USB cables and interfaces are almost the most common things we encounter every day, but there are still many friends who do not understand its basic concepts. Today I will try to clarify this matter for you in the shortest possible time.


The first thing to understand is the USB protocol standard: Many friends know that USB has standards such as 2.0, 3.0 , and 3.1 .

The organization that developed this standard is called USB-IF . It has been scolded miserably in the past two years because it confuses the USB standard too much.

For example, for Wi-Fi, the naming convention has been simplified from the anti-human 802.11n, 802.11ac, and 802.11ax to Wi-Fi 4, Wi-Fi 5, and Wi-Fi 6. It is easy to understand and everyone is happy.



The standard naming of USB is more and more confusing. In 2000, the USB 2.0 standard was born. In 2008, USB 3.0 was officially released. The transmission rate of the interface was greatly increased from 480Mbps to 5Gbps, which is a qualitative leap.


So most friends know that copying files with USB 2.0 is a very painful thing. The actual speed is generally only about 30M per second, while the actual speed of USB 3.0 can easily exceed 100M.


In 2013, USB 3.1 was released, and the interface rate doubled on the basis of USB 3.0, reaching 10Gbps .


At this time, the USB-IF organization started to do things. It renames the USB standard. Rename USB 3.0 to USB 3.1 Gen 1 (the first generation of USB 3.1), and the newly released USB 3.1 standard is renamed to USB 3.1 Gen 2 (the second generation of USB 3.1).



In other words, in the new standard naming, there is no longer the name USB 3.0. This caused the first wave of chaos to erupt. For example, a certain treasure seller will tell you that mine is a USB 3.1 interface, which must be faster than the USB 3.0 next door! Of course it is more expensive!At this time, if we pay the bill because of this, it is an IQ tax.


Now we know that USB 3.0 and USB 3.1 Gen 1 are exactly the same, but with a different name. At present, most of the ports on the market that claim to be USB 3.1 are actually the past USB 3.0.The really faster USB 3.1 Gen 2 is also available. How to distinguish?


The easiest way is to look at the color: the USB socket is black or white, it is USB 2.0, and the speed is the slowest .If it is blue, it is USB 3.0 or USB 3.1 Gen 1 , which is the most common at present. And the fastest USB 3.1 Gen 2, the general interface is red.



When we finally feel that we have memorized the USB naming convention. In 2017, the USB 3.2 standard was born, and the maximum rate was increased to 20Gbps, double that of USB 3.1 Gen 2.


Then, USB-IF came to another show operation. According to the latest naming convention, USB 3.0 and USB 3.1 have completely disappeared in the long river of history, and they have all been included in the sequence of USB 3.2.