You will not be unfamiliar with the USB interface, which can be said to be the most frequently used and most common interface in our daily lives. Whether it is a mobile phone, earphones, or other digital devices such as computers, USB interfaces are basically used when charging, transferring files, or connecting to a PC for flashing. This universal interface technology has indeed brought a lot of convenience to our lives.

Nowadays, the storage space of new smartphones on the market basically starts at 128GB. For users who travel all year round, this capacity is enough for temporary data transfer. Just use a data cable to connect to a PC to play the role of a mobile hard disk, reducing the user's carrying burden.

In fact, even though the current smart phones on the market have basically universalized the USB Type-C interface, the USB transmission speed of most of them still stays at the USB 2.0 standard. In contrast, the USB flash drives, USB docking stations, USB hard disk boxes and mobile hard disks currently on the market have fully transitioned to the USB 3.0 standard many years ago, and the file transfer speeds of the two are naturally different.

The question is, what are the differences between USB 2.0 and USB 3.0? Why do most mobile phones on the market still use USB 2.0? Is USB 3.0 really dispensable for mobile phones? Today we will talk about these issues.

USB 2.0 and USB 3.0

Before we clarify the difference between USB 2.0 and USB 3.0, we need to understand a piece of history. In 1994, in order to solve the various interface problems in the computer market at that time, several giant companies such as Intel, Microsoft, and IBM jointly launched the Universal Serial Bus (USB). Under the promotion of these industry giants, USB's long road of struggle began.

After experiencing the failure of USB 1.0 and the improvement of USB 1.1, in 2000, Intel, Microsoft, Philips, NEC and other giants jointly released the USB 2.0 specification, and in the following days, USB 1.0 was specified as the low-speed version of USB 2.0. USB 1.1 is defined as the USB 2.0 full-speed version, while the real USB 2.0 is called the USB 2.0 high-speed version. From the theoretical data point of view, the transfer rate of the USB 2.0 full-speed version has reached 480Mbps, about 60MB/s, which is about 40 times higher than that of the USB 2.0 full-speed version.

As for the USB 3.0 specification, it was an early term. The USB 3.0 specification was officially completed and publicly released in 2008, and was later renamed USB 3.1 Gen1/USB 3.2 Gen1 by the USB Standardization Organization. According to the official introduction, compared with USB 2.0, USB 3.0 has 5 extra pins for high-speed data transmission, and supports a maximum transmission rate of 5Gbps, about 625MB/s, which is about 10 times higher than the USB 2.0 high-speed version.

Then let's take a look at the actual difference. Although the appearance is the same, from the color point of view, the color of the USB 3.0 interface is blue, while the color of the USB 2.0 interface is mainly white and black. In addition, USB 3.0 uses a 9-pin design, while USB 2.0 uses a 4-pin design, which allows us to judge the type of USB cable by observing the pins inside the interface.

Then, in terms of transmission speed, we specially prepared a mobile phone that supports USB 2.0 and a mobile phone that supports USB 3.0 for comparison. Copy a 1.41G compressed file on both sides. It takes about 2 minutes to pass the USB 2.0 interface. The estimated transmission speed is between 15MB/s-25MB/s. It is difficult to reach the ideal transmission speed of 60MB/s.

For comparison, it takes about 3-5 seconds to transfer the same file through the USB 3.0 interface, and the transfer speed can reach 300MB/s-400MB/s. Although it cannot reach the ideal level of 600MB/s, such a transfer rate is indeed 10 times that of USB2.0.

Finally, in terms of functions, thanks to the characteristics of USB 3.0, mobile phones that support USB 3.0 can output the phone screen to the screen through a wired connection. Compared with wireless projection, the wired video output function is simple and direct, has advantage of low latency and no frozen.

Why not use USB3.0?

Some readers may ask, since USB Type-C has been under the banner of "USB 3.1" since its birth, why are mobile phones equipped with this interface, but the USB transmission speed is still based on USB 2.0?

Before answering this question, we need to understand USB Type-C first. USB Type-C is essentially a USB interface form factor. It has a smaller volume than Type-A and Type-B, and it solves the doubts of traditional USB plugs. However, it is only a physical interface form after all, and there is no correlation between the interface type and the protocol. Whether it is USB2.0, USB3.0 or Thunderbolt 3, it is just an "optional".

Then, let's talk back to the issue of why major mobile phone manufacturers don't use USB 3.0. The reason is very simple. USB 3.0 will interfere with mobile phone signals (including 4G networks and Wi-Fi) and wireless keyboards and mice (including 2.4G, 5G, and Bluetooth) during data transmission. Compared with computers, the communication signal and network quality of mobile phones are obviously more important than the speed of wired transmission.

In addition to faster transmission and video output, USB 3.0 also has a "high current" feature. If you only look at the charging power, USB 3.0 is already a younger brother in front of USB PD/private agreements. In the case that USB PD, public version cable and USB 3.0 are not compatible, fast charging of mobile phones has naturally become the first choice of manufacturers, because this is just needed.

Regarding the issue of why USB 3.0 is not used, industry insiders once said: "The speed of USB 3.0 is meaningless. Now no one uses wired transmission. They are all using wireless transmission. Before, many mobile phones support MHL. The model will support this, and it will be projected to the TV wirelessly."

What's interesting is that even the remaining mobile phones that support USB 3.0 rarely use it as a major selling point and advertise it. For example, Huawei does not promote USB 3.0 at all. Users can only find speed-related instructions in the corners of the parameter list on the official website. Until today, even some smartphones that support USB 3.0 will choose to block this feature by default.

Summary

Some readers may ask, is there any USB3.0 mobile phone on the market that does not emit interference? The answer is still there. As early as 2016, Lenovo ZUK Z2 Pro successfully achieved zero interference with USB 3.0 connection through anti-interference data cable. USB 3.0 is still very meaningful, especially when interference can be effectively controlled, manufacturers should actively follow up this feature, even if the cost is to increase the cost of mobile phones.

Of course, some people may say that I can't use this, and it has no actual impact on me, but that is only for some people. Basically, mobile phones in this era cannot be inserted into memory cards. For users with too much data, every time the phone is changed is a torture. When you watch your 50G data squirming on the progress bar and stare at the remaining time for more than four hours, you will be eager for your mobile phone to have a USB 3.0 interface.