Everyone knows that USB has various connectors:
It is mainly divided into Type A and Type B, and there are subtypes of Micro/Mini under it. A real-life example is: the USB cable connecting our mobile phone and computer has USB A on one side and USB Micro B on the other. The introduction of Type C seems to mean that there is only one more shape of USB connector, and its relationship with the USB 3.0/3.1 protocol should be an inclusive relationship, that is, Type C is just an additional interface defined by the USB 3.0/3.1 protocol. In fact, this understanding is wrong. In fact, USB Type C is not equal to Type A/B when it was first proposed. It has its own protocol and spec. Only it can support the USB Power Delivery spec ("USB PD") fast charging protocol, and only it can provide video output such as DisplayPort. It is the direction of the future. This article will explain its various details one by one.
USB Type C vs USB 3.0/3.1
After years of development, USB can be found on almost all electronic devices. It is also constantly evolving and its speed is constantly increasing:
The latest USB 3.1 provides a transmission speed of 10Gbps. As mentioned above, its interface has Type A and B. There is a big problem with these two sets of interfaces, that is, they are directional and cannot be plugged in reverse (of course, they cannot be plugged in).
I believe everyone has had the bad experience of groping in the dark to plug in the USB cable. In this regard, Apple's lighting interface is very good, the front and back are the same, and you can plug it in at will. Now Type C brings the same features:
Its shape is also flatter, which is convenient for making devices thinner. Note that Type C is not bound to USB 3.0/3.1. In theory, Type C can also be applied to USB 2.0 or even 1.1. It doesn't care which protocol is transmitted on it. In this regard, Type C is just a more convenient new USB interface. In addition, it provides more new features besides Type A/B.
More convenient connection
When we usually use USB, the general method is to connect the PC as the host with Type A and the device with Type B:
One side is different in shape, and there is absolutely no confusion, but you have to pick it up and check it every time to make sure you have taken the right one. In contrast, Type C is the same whether it is plugged in the right or wrong direction. There is no difference between the master and slave devices. You can plug it in on both sides. You can use it without even looking at it. It is very convenient.
Power Delivery (PD) Fast Charging Technology
When USB PD 2.0 was announced in 2014, it explicitly required that it only support Type C (reference 1). That is, the Type A/B connector can support USB3.1 10Gbps speed, but cannot support PD fast charging. It can only use the old Battery Charging Specification ("USB BC") charging protocol.
PD 2.0 communicates the charging protocol by reusing the CC signal line.
When both ends handshake and agree, it can provide up to 20V, 5A, and a total of 100W of power. It is enough for laptops and low-power desktops. This is a big step up from traditional BC charging.
Note that PD charging is very different from other fast charging. Qualcomm's Quick Charge and PE both transmit charging protocols through traditional D+ and D- lines, which are difficult to be compatible with PD. Qualcomm even turned to PD in QC 4.0 (Reference 2). A small battery is added next to the USB 3.1 logo that supports PD charging:
The feature that PD can provide 100W of power creates another possibility. That is, the laptop power cord and USB data cable are combined into one:
The Dock can charge the laptop and can also be used as a USB Hub, which reduces the connection cable of the laptop. In fact, Apple has done this more than two years ago (Reference 3):
The ultra-thin MacBook has only one USB Type C interface, which is responsible for power supply and data at the same time. The minimalist design is shocking.
Great scalability
When the USB 3.0 protocol was announced, an "Alternate Modes" was proposed, which means that other protocols can be attached to the USB protocol for transmission. At that time, it was just a possibility, but it was truly implemented on Type C. It is the display interface protocol Display port on Type C. For those who don't know Display Port, please refer to: The mystery of display resolution: Who determines the size of display resolution?
Because DP and Type C are very similar at the physical layer, a simple conversion can be done:
Type-C and Thunderbolt
Finally, let's look at a controversial topic: Which one is more promising, USB or Thunderbolt? Obviously, this is a question of public opinion and private opinion.
Thunderbolt currently has great advantages in technology. The first is speed. Thunderbolt 3.0 is four times faster than USB 3.1:
It also supports convenient daisy chain expansion and PC direct connection high-speed data transmission functions, which are not available with USB protocol (Hub required), but are very needed by professional users. It can also attach other protocols to the Thunderbolt protocol, such as DP, etc., and has good scalability. At the same time, its disadvantage is also very prominent, that is, it is expensive. Currently, the only big players are Intel and Apple, and the transmission speed of up to 40Gbps is an overkill in many cases. The 10Gbps of USB 3.1 is completely sufficient, and only professional multi-screen 4K players need it.
Their future is still unclear. In many cases, it is not the strongest technology that wins, but the result of industry competition. We still need to observe for a while.
Conclusion
Martin Luther King said "I have a dream". I also have a dream, that is, there will be fewer wires behind the computer, preferably no wires. Because there are too many and too messy!!! Wireless charging is not mature at present, but USB Type C has taken a big step towards having only one wire for the computer. One wire can handle power supply, data transmission and display:
I believe that in the near future, the situation of wires being tangled will become less and less!