https://www.ithome.com/0/451/062.htm
In March this year, USB Promoter Group (Leading Group) first published USB4 specifications, the next generation of USB architecture. In early 9, USB Promoter Group released their final USB4 standards, no accident, then, next year will not be too late, you can use the device based on USB4.
But before that, I believe that many small partners for USB4 not yet understood, including the previous USB 3.1, USB 3.2 understanding of the concept of class is relatively vague, IT today home to around USB4 Xiao Bian wish to do some introductory help It was recognized that the nature and advantages of USB4.
History: complex confusing name
First of all, we are talking about USB4 refers to the USB transmission standard, is a protocol specification and USB transmission performance and performance-related, USB4 this specification can be understood as "fourth generation."
USB transfer protocol is in 1994 jointly developed and specified by Compaq, DEC, IBM, Intel, Microsoft, NEC, and Nortel and other companies, and in 1994 November 11 announced a USB V0.7 version. Later, the companies established in 1995, a non-profit organization to promote and support a USB-called USB Implementers Forum, that is, we are familiar with USB-IF, USB-IF is now the USB standards organization.
USB-IF in 1996 formally proposed USB1.0 specification, but was USB1.0 transfer rate of only 1.5Mbps, the maximum output current 5V / 500mA, to support USB peripheral devices and then very rarely, so rarely motherboard business USB interface design directly on the motherboard.
USB 1.0
In September 1998, USB-IF USB 1.1 specification released, increase the transfer rate to 12Mbps, and some of the technical details of USB 1.0 was amended, the maximum output current is still 5V / 500mA.
To April 2000, USB 2.0 standards promulgated, the transmission rates of up to 480Mbps, is 60MB / s, is 40 times that of USB 1.1, the maximum output current of 5V / 500mA, while using 4-pin design. From the introduction of USB2.0 is still in service, it can be said to be the oldest of the USB standard.
From the beginning USB2.0, USB-IF on the show was renamed in terms of their "unique talent."
June 2003, USB-IF renamed USB specifications and standards, the USB 1.0 renamed USB 2.0 low-speed (Low-Speed) version, USB 1.1 was renamed the USB 2.0 Full Speed (Full-Speed) version, USB 2.0 Ze It is a high-speed USB 2.0 (High-Speed) version.
But this was basically nothing changes for now affected, because USB1.0 and 1.1 has been basically quit the stage of history.
In November 2008, by Intel, Microsoft, Hewlett-Packard, Texas Instruments, NEC, ST-NXP industry giants such as the composition of USB 3.0 Promoter Group completed the USB 3.0 standard and publicly available, foreign title is SuperSpeed. USB Promoter Group is mainly on the development of USB series of standards and the development of standards will eventually be handed over to the USB-IF to manage.
USB3.0 maximum transfer rate of 5.0Gbps, i.e. 640MB / s, the maximum output current of 5V / 900mA, 2.0 backward compatible, and supports full duplex data transmission (i.e., can receive data and send data simultaneously, USB2.0 is semi-double characteristics of workers), have better power management capabilities.
9-pin design USB3.0, USB2.0 and 4 as front, 5 is specially prepared for the later USB3.0, USB2.0 and it can be determined by USB3.0 pins.
July 2013, USB 3.1 release, transfer speed to 10Gbps (1280MB / s), known as SuperSpeed +, while the supply of the highest standards to allow the 20V / 5A, that is 100W.
USB 3.1 compared to USB 3.0 upgrade is also very obvious, but it did not take long, USB-IF USB 3.0 will be renamed USB 3.1 Gen1, USB 3.1 was renamed USB 3.1 Gen2.
The renamed to consumers in trouble, because a lot of profiteers in product packaging are marked only supports USB 3.1, no explanation is Gen1 or Gen2, in fact, a big difference between the two transmission performance, consumers believe it will into the pit. So, this was renamed for the majority of consumers, it is a Hunzhao.
The time came in September 2017, USB 3.2 release, support for dual-channel 10Gbps transmission data in the USB Type-C, speeds of up to 20Gb / s (2500MB / s), maximum output current is 20V / 5A, there are other minor improvements .
USB renaming process
However, in 2019, USB-IF renamed again, they would USB3.1 Gen 1 (that is, the original USB3.0) changed its name to USB 3.2 Gen 1, USB 3.1 Gen 2 (formerly USB3.1) renamed USB 3.2 Gen 2, and USB 3.2 were renamed USB 3.2 Gen 2x2.
People can not buy a good line of data? !
USB historical summary of what version features:
Present and future: USB4 leap elevator
Finally comes the USB4, then this next-generation protocol standards which upgrades to improve it? First, it is certain that, since it is from "3" to "4" crossgrade, then the magnitude of improvement is not necessarily small.
IT homes here Xiaobian have mastered the comprehensive variety of information on the new features USB4 to sort out as follows:
1,40 Gbps maximum transmission speed:
Dual-channel transmission, the theoretical maximum transmission speed of USB4 should reach 40 Gbps, the same speed and the Thunderbolt 3 (hereinafter "Lightning 3" name).
USB4 will actually have three speeds: 10 Gbps, 20 Gbps and 40 Gbps. So you want to buy the highest transmission speed is 40 Gbps equipment, the best check out the specifications before you buy.
2, 3 and lightning can interface is compatible with:
Some (not all) can also be compatible device USB4 Lightning 3 interfaces, which means that there USB4 interfaces on your device, there may also be an external device 3 can be lightning. But this is not mandatory, specific or not compatible, it depends on the attitude of the equipment manufacturers.
3, dynamic bandwidth resource allocation capabilities:
If you use USB4 port also use it to an external display and transmission of data, the port will be allocated bandwidth is appropriate under the circumstances. For example, if only 20% of the video bandwidth required to drive the display 1080p, then the remaining 80% of the bandwidth can be used to do other things. This is impossible in USB 3.2 and earlier era, before that, USB works are to take turns to come.
4, USB 4 devices will support USB PD
USB PD is the USB Power Delivery (USB power transmission), is one of the fast charge current mainstream protocol, which is developed by the USB-IF organization, the specification enables higher voltage and current, maximum delivery of power up to 100W and free to change the direction of transport of electricity.
Under the USB-IF, the current USB PD charging interface standard form should be USB Type-C. There are two pins in CC1 and CC2 USB Type-C interface, the role of PD is configured for communication channels.
5, using only USB Type-C Interface
With the above characteristics of this one, it is natural, we can know, USB4 can only be run through the USB Type-C connector, in fact, not only USB PD, the latest standards in other USB-IF's also only apply to Type-C.
6, can be backward compatible with past agreements
USB4 USB 3 can be used with devices and USB 2 and port. That is, it is backward compatible to the previous protocol standards, but USB 1.0 and 1.1 do not support the current market also use the interface to such an agreement has almost disappeared.
Of course when the device is connected to the USB 4 USB 3.2 port, which can not be delivered at a rate to 40 Gbps, while the older USB 2 interfaces will not connect it to the interface USB4 becomes faster.
7, and lightning 3 What is the relationship? Cost Zeyang?
At present it is certain that the cost USB4 is higher than USB 3.2, although uncertain and PC vendors to add 4 USB interface specific costs will increase in number, but we also can refer to reference Lightning 1-3
In March, Intel technology will be Lightning 3 "donate" to the USB-IF organization (of course, Intel USB-IF he is the lead brother), shortly thereafter USB4 specification will come out, in fact, is the use of USB4 Lightning 3 agreement difference is small. Intel is also a move to further popularize Lightning 3 interfaces, to lay their own "unified" position.
Of course, with USB4 large-scale use in the future, the cost is bound to come down, which is Intel would like to see.
8, on naming
This year USB4 standard wording is "USB4", rather than "USB 4", with no spaces. For this, USB Promoter Group CEO Brad Sanders (Brad Saunders) explained that the aim is to remove the spaces will shift the focus from the version number to the brand name.
He said: "One of the signals we want to convey is that we are not going to get into the iterative path 4.0,4.1,4.2 ...... and we do not want it associated with specific products ...... We want to make it as simple as possible."
I hope this man meant it right.
9. When can I use?
Despite the current USB specification 4 has been released, but in 2020, we are almost impossible to see USB4 products to market. According to the introduction Sanders, the typical development cycle of new products is 12-18 months.
As support for laptops and desktop USB 4, it might take longer time. For example, standard USB Type-C of 2014 announced, while the USB Type-C into the mainstream took a long time, and now many laptops still no USB Type-C interface.
These are the IT house small series have mastered the current information about USB4 standard protocols, and more specifically the technology has not been announced, of course, I believe that the average consumer there is no special need to understand.
It is undeniable that, prior to the sort of history can also be seen, USB standard digital upgrade each iteration, functionality and performance will have a leap forward in the promotion, the USB4 no exception, at least, from now to know information is still very people look forward to meet the future needs of all aspects of the device is connected few years, data transfer, charging and so on should not be a problem.