From Type-A to Type-C, the history of USB interface development

USB is the most widely used interface at present, and every iterative update will cause heated discussions. Now that the USB Type-C interface has become the mainstream, a question arises. There is Type-C, so what are Type-A and Type-B? A, B, and C three types of updates, what happened to the USB? Let's move on.

1. What are Type-A, Type-B, and Type-C?

To understand the course of their history, one needs to know what they looked like in advance. In fact, it is very convenient to distinguish. Just read the picture below.

So we understand that Type-A is actually the most used "standard" USB interface before. The English name of Type-A interface is "Standard Type-A USB", and other interfaces are just its derivatives.

For the Type-B USB interface, although its appearance rate is far lower than that of the standard Type-A interface, everyone must be familiar with it, because many external USB devices such as printers and monitor USB HUBs use Type-B USB interface. Generally speaking, the USB ports on PCs are standard Type-A, while external devices mostly use Type-B.

When it comes to Type-C, it completely changes its appearance. Smaller size, even comparable to Mini-USB and Micro-USB. It has more functions and is more convenient to use. I won’t introduce more specific data information.

2. The evolution of the USB family

Since the development of the USB family, there have been too many interfaces worthy of detailed analysis. Since USB4 was launched soon, we will not put it in the picture. The picture below can roughly summarize the size of the USB family.

The Mini-USB and Micro-USB we often use are born according to the USB2.0 transmission protocol, and they are also divided into Type-A and Type-B respectively. In the era of USB3.0, due to the improvement of the transmission speed and the improvement of the pin position, only the Type-A USB3.0 interface remains the same as the previous shape, and the Type-B and Micro-USB have changed their appearance (increased volume) ).

Mini-USB and Micro-USB have a lot to do with Type-A and Type-B, so let's analyze them separately.

(1) Mini-USB 2.0 interface

Premium USB Mini Type B 5-Pin Cable, Male/Female

Mini-USB interface is also an interface we are very familiar with, it is widely used in digital products, such as MP3, digital camera and mobile hard disk, etc.

Compared with standard USB interface and Type-B USB interface, its volume is greatly reduced. Maybe most of the Mini-USB interfaces you see are Mini-B type.

(2) Micro-USB 2.0 interface

LSZH USB Cable, Type A/5-Pin Micro-B

Mini-USB interface is divided into A/B, and Micro-USB is no exception. The Micro-USB interface is an improved version of the Mini-USB interface, which reduces the size again and is more suitable for mobile devices that are becoming thinner and lighter.

Most of the current devices use Micro-USB interface, and Mini-USB has basically been eliminated. Similarly, the Type-B type of the Micro-USB interface is also an improved version of the Type-A type.

Next, let's go back to USB Type-B.

Due to the large size of the standard Type-A USB interface, its appearance has not changed when it is developed to USB3.1 today. However, USB Type-B is a bit different. It has a very unique shape and does not reduce too much volume. When it comes to USB3.0, it is natural to change the internal structure to increase the transmission speed.

3. Significance of the new generation USB Type-C

USB 3.1 Type C Male/Male

The Type-C interface and the USB3.1 standard were introduced almost at the same time, and the Type-C specification is indeed formulated according to the USB3.1, so USB3.1 can of course be made into the Type-C type, but what needs to be understood is: Type-C Not equal to USB3.1.

USB3.1 has three connection interfaces, namely Type-A (Standard-A), Type-B (Micro-B) and Type-C. Type-C greatly reduces the physical appearance and is more suitable for short and thin handheld devices. Type-C will replace the Micro-AB connector (supports direct transfer of USB devices without the intervention of the main control system), It will also replace the general Micro-USB connector. The Type-C imitates the Apple Lightning connector. Both front and back can be connected and used normally. It is more ideal than the existing Micro-USB. Although Micro-USB has a foolproof mechanism to prevent reverse connection, but The benefits of positive and negative connection are better than preventing reverse connection. Good-quality Type-C cables also have enhanced EMI and RFI suppression features.

Now with the emergence of USB4, various specifications have gradually begun to be integrated, and the Type-C interface has secured its position. Will the physical interface become more uniform in the future? We will wait and see.