The development history of USB and Lightning interface specifications

For Apple in 2020, is an extraordinary year, for the first time in the autumn held three conference, issued a series of blockbuster products, regular update of Apple Watch and appearance, the great change of the iPhone 12 series, as well as the most important of the research of M1 chip based on Apple MacBook Air, Pro, as well as the Mac mini, whether it is for Apple itself or the entire sum of electricity industry is a big shock.

A series of actions of Apple are also practicing the concept of Apple, creating product ecology and using a full range of services.

Apple’s M1 chip is a big move, but there’s a difference. The introduction of the new MacBook has already changed the interface description to two Thunder /USB4 ports.

Both USB4 ports support charging, DP video transmission, Thunderbolt 3 protocol, and USB3.1 Gen 2.

What is USB4?

It appears in the latest version of Apple’s Mac product, does it also represent the latest transport standard? Today, let’s talk about the history of transport standard.

1.History of physical interface changes

USB port is one of the most common ports in life, whether it is charging or data transfer.
But whether it’s charging or transferring data, A simple USB-A port also comes in many varieties.
Universal Serial Bus is the full name of USB, and the Chinese name is Universal Serial Bus. It was jointly proposed by Intel, Compaq, IBM, Microsoft and many other companies at the end of 1994.
USB interface is widely used, widely used in personal computers, mobile devices and other information and communication products, and extended to photography equipment, game consoles and other related fields, is also one of the most common interface types.

At present, the common USB-A interface internal white base, of course, there are other color matching interface.
It can be seen from the above figure that there are four contacts inside the USB-A interface, of which the two contacts on both sides are slightly longer, and the two contacts in the middle are slightly shorter.
This is because the longer contacts on either side are responsible for the power connection and the two smaller contacts in the middle are responsible for data communication.
So in principle, disconnect data transmission first when unplug wire, power off again, can prevent data damage.
The USB-A interface with 4 pins inside is also one of the most widely used and longest used interfaces.
There are still a lot of devices in use until 2020.

Then big companies like USB-IF and Intel pushed USB-A, and A new type of interface emerged.
The size of the entire interface remains the same, but the number of internal contacts has been increased from the previous four to nine, and the performance of the USB-A interface has been greatly enhanced.
The USB-A interface was developed early and was promoted by many technology giants, so it became popular quickly.
However, the USB-A interface is not perfect either. The interface is large in volume and does not support blind plug. Therefore, it is believed that many users need to try twice or even three times before they can connect successfully.

The emergence of US-C completely changed this situation, USB-C full name USB Type-C, also known as Type-C.
Is a new type of physical interface with specifications published by USB-IF, the USB standardization organization.
Compared with USB-A, USB-C has the characteristics of small size and support for blind plug, which completely solves the century-old problem of “USB can never be plugged in”.

Because of that makes the USB – C can be used on many devices, USB today in 2020 – C interface has been very popular, but the USB – C really first appeared in front of the public is in 2015, the first USB mobile phones Letv super – C 1, the first USB – C laptop New Macbook, the first tablet Nokia N1, the first USB – C charger 29 w, the first Apple USB – C bao yu bo YB – CP1, the forerunner to the rapid expansion in the USB – C interface in the future.

Compared with USB-A, USB-C not only has smaller physical interface volume and supports blind plug, but also can accommodate more pins inside.
Due to the smaller size of a single pin, up to 24 pins, or pins full of pins, can be accommodated inside the USB-C connector.
The more pins you have, the more features you can achieve, which we will discuss later.
However, from the update iteration of devices and interfaces launched in 2020, USB-C will replace USB-A to become the interface type of the new generation of public popularity.

Because USB1.0 and 1.1 are so old, I’ll just skip over and start with USB2.0.
USB2.0 comes in the form of A USB-A physical interface. As mentioned above, the original USB-A interface had only four contacts inside for power and data transmission, and of course, the maximum output current was only 5V 500mA.

By USB3.0, the number of pins inside USB-A was increased from 4 to 9, and the charging performance was also improved, supporting A maximum of 5V 900mA charging, although the improvement is certainly not good enough for now.
This is why plugging the data cable into the USB-A interface of the laptop or desktop case is slow to charge, because the current is small and only at the level of charging.

The regular USB-A interface does not support high charging (leave aside the magic change USB-A), and USB-C and PD appear.
The appearance of USB-C makes charging different. It can support the power transmission of 20V5A and 100W at most. The appearance of USB-C instantly improves the charging power qualitatively.

3. USB interface transmission rate improvement

Some common interface types have already been covered, but USB-A to USB-C is A big interface iteration.
Each physical interface also has different functional characteristics due to different internal pins. Here are the differences in the transmission speeds supported by these physical interfaces.

USB2.0 is the most common transmission speed standard, but is there 2.0 or 1.0?
There was one, but it was forgotten because it was so old and slow to transmit.
The original USB1.0 was launched in 1996, but the transmission speed was only 1.5M/s.
In 1998 it was upgraded to USB1.1 and the speed was increased to 12M/s. Now USB1.0 and 1.1 are very rare

The USB2.0 specification, which evolved from the USB1.1 specification, was introduced in 2000.
USB2.0 increased the speed to 480Mbps, or 60 Mbps, known as Highspeed. This protocol is the oldest standard in existence, and most USB-A interfaces will still be using USB2.0 in 2020.
It is important to note that the above naming conventions for USB1.0, USB1.1, and USB2.0 are reasonable, and the corresponding transfer speed standards are well understood.
Since USB3.0, transmission speeds have gotten faster and naming conventions have become more numerous.

In 2008, USB 3.0 was jointly developed by Intel, HP, NEC, NXP Semiconductors and Texas Instruments. It was launched by USB-IF in November 2008.
The release of USB3.0 increased the speed standard from 480Mbps to 5Gbps, or 625 Mbps. The speed was faster and the name was updated. The new USB3.0 speed standard is called SuperSpeed.
However, the name of USB3.0 was changed twice by USB-IF, the first time USB3.0 was changed to USB3.1 Gen 1, the second time USB3.1 Gen 1 was changed to USB3.2 Gen 1.
According to the USB-IF, the purpose is to unify the naming convention, but in the end, users will not be able to accurately tell which is the USB3.0 standard.
The name has been changed twice, but the transmission speed standard is still 5Gbps, which is the same.

In 2013, USB3.1 was released, doubling the data transfer standard from 5Gbps to 10Gbps, or 1250MB/s. This standard is also known as SuperSpeed+.
However, since then, USB3.1 has been renamed USB3.1 Gen2 and USB3.2 Gen2 by USB-IF. Although the names have been changed twice, the transmission speed standard is still 10Gbps, which is the transmission speed of USB3.1.

In 2017, USB3.2 was released, raising the transmission speed standard from USB3.1’s 10Gbps again, and again doubling it to a maximum of 20Gbps, or 2500MB/s.
Well, yes, USB-IF has changed its name again, but only once, namely USB3.2 Gen2x2.
Again, despite the name change, the standard transmission speed is still 20Gbps, USB3.2.

Four, a new way of Apple and thunder interface

Compared with the development of USB protocol, the development of Thunderbolt interface is much simpler.
From the founding of Apple in April 1976 to the launch of Apple I in 1976 to the release of the first iMac in 1998 to the launch of the iPhone in early 2007, a series of actions by Apple show that Apple does not follow the trend in many cases, but stands out and leads the trend.
The reason Apple is mentioned in the introduction of the Lightning interface is because Apple is one of the creators of the Lightning interface.
The Thunderbolt connector is a word you often see when browsing Macs on Apple’s website.
In 2011, Thunderbolt, a collaboration between Intel and Apple code-named Light Peak, was unveiled.
Moreover, Thunderbolt interface integrates two communication protocols, PCIE and DisplayPort, so before full-function Type-C, Thunderbolt interface is a rare multi-functional interface that supports high-speed data transmission and video/audio transmission at the same time, that is, it has input/output functions of USB and DP or HDMI/DVI/VGA transfer at the same time.
And because its bandwidth reaches 10Gbps (Thunderbolt 2 is 20Gbps), it can be said to be a very advanced interface expansion technology, and such excellent performance is doomed to make Thunderbolt interface will lead the trend.

In the period of Thunder 1 and Thunder 2, the physical interface of Mini DP was basically carried on the MacBook laptop computer.
And there’s a lightning bolt with an arrow on the edge of the interface.
However, at that time, due to the scarcity of Lightning interface related devices, even if they were equipped with them, they were all on high-end devices. Moreover, due to the high price of Apple MacBook laptop, its popularity was not high among the mass user groups, and it was seldom paid active attention by user

The interface became familiar to users during the Thunderbolt 3 phase, because it also used the more versatile USB-C physical interface.
But at the time, since Thunderbolt 3 was not yet as widely known, many users associated USB-C with Thunderbolt 3 and were confused.
In fact, it is easy to understand that the physical interface of Thunderbolt 3 must be USB-C, but the physical interface of USB-C does not necessarily support Thunderbolt 3.

Thunderbolt 3 is currently the most comprehensive protocol, whether it is the transmission speed, video expansion or charging is the top performance of the interface protocol.
But the Thunderbolt 3’s USB-C ports are mostly found on a variety of high-end devices, such as Apple’s MacBook laptops or iMacs.
And Thunderbolt interface support PCIE communication protocol, so Thunderbolt 3 interface can also directly connect to the external graphics card.
In principle, the more functions an interface supports, the more powerful the performance, and there should be a lot of people like to use it.
But the fact is not so, why many people can not use, a large part of the reason is that the price problem leads to many manufacturers and users hope to stop.
That’s because Intel holds the patents on the Thunder 3 interface, so vendors who want to use the standard have to pay a hefty licensing fee to Intel.
That’s not all. The Thunder 3 interface requires a separate control chip, so if a vendor wants to use the Thunder 3 interface standard, they will have to pay a cost on the chip and a licensing fee (which is why the equipment with the Thunder 3 interface and the Thunder 3 wire are expensive).
Is it possible to change that?
Indeed, the USB-IF group released the USB4 specification in September 2019, which drastically changed the huge cost of the Thunderbolt 3 interface standard.

Uniform USB4/ Lightning 3

In September 2019, the USB-IF organization released the USB4 specification. USB4 integrates Thunderbolt3’s advanced technology, directly delivers super-bandwidth data transmission capability, supports the same video expansion capability as the Thunderbolt3, and has a charging capability.
It can be said that a fully functional USB 4 interface is the most complete, the smallest volume, the fastest physical interface.
And downward compatible USB 3.2, 3.1, 3.0, 2.0, compatible with Lightning 3.

Why are Thunderbolt 3 and USB4 in the same subtitle?
In March 2019, Intel announced the opening of the Thunderbolt protocol to USB-IF. USB4 has all the features of Thunderbolt 3 and is free to the public.
In the future, many manufacturers can use the USB4 interface standard to obtain the high performance standard of Thunderbolt 3, which is bound to make the further popularization of Thunderbolt 3 and accelerate the landing of high performance interface standard.

Six, one interface to go the world

A laptop is equipped with a port that takes care of charging, transmitting data, and expanding video, and can do all of these tasks with better performance, so far only the USB-C port is equipped with the USB4 specification.
The 100W power charge, 40Gbps data transfer speed, and the ability to extend the 5K resolution of the display also make it the most powerful interface available.

The first New MacBook equipped with USB-C interface in 2015, the first MacBook Pro equipped with Thunderbolt 3 in 2016, and the MacBook series laptops equipped with self-developed M1 chip and USB4 interface in 2020.
Apple has been at the forefront of promoting Thunderbolt 3/USB4.
It is believed that the launch of USB4 will further popularize the performance standards of Thunderbolt 3, and more and more users will use the performance standards of Thunderbolt 3.

At the end of the article, let’s use a picture to understand the history of USB and Lightning interface standards. Because the original USB1.0 and USB1.1 are too old, they are not included in the statistics.
From the early USB2.0 to the latest USB4, from the Thunder interface to the Thunder 3 interface.
The reason for putting USB4 last in the table is that it is a trend towards a unified interface specification, which will accelerate the adoption of Thunderbolt 3 and enable more users to use the high performance standards of USB4.

Summary of charging head network
From USB1.0 to USB4, USB protocol specification has gone through nearly 24 years, the transmission standard from 1.5Mbps to the current 40Gbps, charging from the beginning of the 5V500mA to the current 20V5A.
USB protocol specification is also in continuous development, the current charging and transmission speed has been more than 27,000 times the original, we are witnessing the development of USB protocol specification at the same time also enjoy the convenience it brings.
However, Apple did not intend to take the road of USB protocol specification from the very beginning in the field of protocol specification, so it developed the Thunderbolt standard with Intel, and it has been far ahead since its birth.
Although leading the pack, the Thunderbolt has remained elusive to the masses due to hardware and cost, and is only available on high-end models such as Apple’s MacBook laptops.
In 2019, USB-IF launched the USB4 protocol specification, which completely changed the situation that Thunderbolt 3 could not be popularized.
It is believed that in the future, USB4 will be widely used, and manufacturers will be able to produce product accessories and hardware products with USB4 protocol specifications without paying high licensing fees, and the performance standard of Thunderbolt 3 will also be used by the public with the popularity of USB4.
As manufacturing costs fall, so does the price of Lightning’s products.
This will accelerate the adoption of USB4, and enable the performance standards of Thunderbolt 3 to be realized quickly, allowing more and more users to enjoy the different use experience brought by high performance.
The USB-C interface is already widespread, and the Thunderbolt 3-compatible USB4 protocol specification will be widespread.
In the future, users will only need one USB4 cable for charging, data transmission and video extension.
And the charging power of up to 100W, data transmission speed of 40Gbps and video expansion of 5K will make users further experience the convenience.


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