Before opening this article, let me introduce you to usb USB, which is perhaps the "most familiar stranger" in everyone's life. Do you know? In fact, the full English name of USB is Universal Serial Bus, and the Chinese translation is Universal Serial Bus.
The most familiar stranger | Source: sohu.com
Translated into a language that human beings can understand: an interface technology that has been agreed upon by many industry leaders, can integrate many protocols together, and realizes the plug-and-play connection of computers and external devices.
With the popularity of new types of smart phones, mobile phones have gradually become indispensable and important assistants in our daily lives. This, too, has directly led to Type C becoming the most familiar type of interface in our daily lives.
USB Type C | Source: image.baidu.com
In fact, calling it Type C is not precise enough, this common mobile phone charging cable interface should be called USB Type C. But have you ever thought that USB Type C is so widely known, where is USB Type A and USB Type B?
Could it be that in the long river of historical progress, a big stride of development has been achieved, and small A and small B have crossed over? Or does this C not represent "generations", but rather has other meanings?
Many questions | Source: image.baidu.com
In fact, the answer to the above two questions is no. Small A and small B are in the same place, and C is indeed lined up with small A and small B. Let's re-recognize USB Type A and USB Type B.
All kinds of USB ports | Source: zhidao.baidu.com
Here to say a little more, like Type A, Type B, Type C, which is actually about the version of the USB interface form, showing the different aspects of the interface; and 2.0, 3.0, these are the versions of the USB interface specification. Speaking with data, USB2.0 theoretical bandwidth is 480Mbps, while USB3.0 can reach 5Gbps, so there are leaps and bounds in data transmission capabilities and transmission speeds.
So, re-recognize: standard USB, in fact, its full name should be called: USB Type A. From the USB 2.0 era to the USB 3.0 era, although its performance has been improving, its appearance has not changed. Note that the commonly used USB Type A interface is also divided into male and female.
Take our common charging cable as an example, this week's square, four sides are very smooth pluggable charger plug or one end on the computer, is the male head. Admittedly, the male head is generally used in small peripheral devices such as mice and keyboards, or as the end of a cable. The following four sides with U-shaped shrapnel is the female head, which is often used in the upper end equipment such as hosts or hubs.
USB Type A | Source: Zhihu, image.baidu.com
In the USB 2.0 era, USB Type B still looks a bit of a big forehead, and in the USB 3.0 era, USB Type B has become a very small Qi bangs.
Moreover, the use scenarios of USB Type B and USB Type A are different, such as printers, scanners and other larger external devices. In fact, USB Type B is also divided into two kinds of male and female, male is very common, female is relatively rare.
But if you say that the usb type B and USB type A interfaces work, in fact, they are 4 pins, so the difference in functional performance is not very large. As for why USB Type B and USB Type A appear, visual inspection may be to achieve the division of different functions of the interface.
Talk about USB Type C in detail, it appears after USB 3.1, but from the appearance point of view, it has a smaller volume than Type A and Type B, and it is not distinguished in the design, so the plugging and unplugging speed will be faster and more convenient to use.
Take another look at the performance of USB Type C, which has 24 pins inside, allowing for more types and faster data transfers and exchanges. It uses the USB 3.1 standard, so the theoretical upper limit of data transfer is 10Gbps, which is exactly double that of USB 3.0.
The standard specification cable equipped with a Type C connector can also be improved by current, and also supports "USB PD" that exceeds the existing USB power supply capacity, which can provide a charging power of up to 100W, truly realizing the "charging for 5 minutes and talking for two hours" of smart phones.
USB Type A | with USB Type B Source: bbs.21ic.com
Type A-C | Source: Zhihu
Through the above two figures, we can clearly see that it is not that a certain interface form absolutely corresponds to USB 3.0 or USB 2.0, but the general requirements of USB 3.0 will also be designed to be backward compatible with USB 2.0 or even USB 1.0.
But in comparison, at present, our more and more common USB Type C interface can already achieve a number of functions that other USB connector types cannot achieve, not only can make smart phones and laptops quickly powered by USB, but also can achieve faster and faster transmission speeds.
So, will the near future be the world of USB Type C? Xiaobian thinks it is very likely, so let's wait and see!
We'll see | Source: n.m.sohu.com
bibliography:
[1] What is USB Type-A/B/C interface connector[ONLINE]. Available at: https://blog.csdn.net/junyeer/article/details/53338801,2019-09-05.
[2] Difference analysis between USB type-C, type-B and type-A[ONLINE]. Available at: https://zhuanlan.zhihu.com/p/160277569.2020-07-15.
[3] USB Type A/B/C basic knowledge and differences between versions[ONLINE]. Available at: https://blog.csdn.net/junyeer/article/details/53338801.2016-11-25.
[4] Iozzio, Corinne. WHAT IS USB TYPE C? [J]. Popular Science,2014,284(4).
[5] What is USB Type-C? [ONLINE]. Available at: https://zhuanlan.zhihu.com/p/28974787.2017-09-13.
The reproduced content represents the views of the author only
Does not represent the position of the Institute of Physics, Chinese Academy of Sciences
Source: Institute of Semiconductors, Chinese Academy of Sciences
Edit: Cloud open leaves fall