What Is Usb Type C Port？

USB type-C is a USB interface appearance standard. It has a smaller volume than type-A and type-B. it can be applied to both PC (master device) and external devices (slave devices, such as mobile phones).

1. Pin definition

To understand the principle of type-C, we must first understand its PN definition. The type-C port has 4 pairs of TX / RX branch lines, 2 pairs of usbd + / D -, a pair of SBU, 2 cc, 4 VBUS and 4 ground wires.

Of course, if the receiver only needs DP signal and does not need USB 3.1 signal, DP can use all 4 pairs of TX / RX differential lines for output, so as to realize DP output of up to 4 lanes, provide total output bandwidth of up to 32.4gbps (8.igbps can be output for each lane), and easily realize 5kx3k60 frame video, or even up to 8K × 4K 60 frame video (4:2:0 data). This mode is dponly mode [2]. In addition, in order to be compatible with USB2.0, type-C also retains the usbd + / D-signal for USB 2.0 devices, so only use the interface of type-c. USB2.0 and even USB 1.0 devices can support front and back insertion. It is worth mentioning that DP + USB2.0 mode can be realized by using usbd + / D - in combination with DP only mode above. DP occupies 4 pairs of TX / RX differential lines, and USB only uses D + / D - [2]. Normally, the USB2.0 differential signal will only be connected to one side, because the USB type-C plug has no B6 and B7. Usb3.1 uses only two pairs of TX / RX differential lines as data lines. It is connected to TX1 / rx1 during forward insertion and TX2 / rx2 during reverse insertion. It can be seen that in any case, two pairs of differential lines are not used. DP alternating mode is to load DP signals onto these two pairs of "redundant" differential lines, so as to realize the simultaneous operation of USB 3.1 + DP.

Type-C also provides 2 cc lines and 2 SBU lines. CC line is mainly used for the communication of power delivery module (hereinafter referred to as PD). CC line is first used to judge the direction of equipment insertion: forward insertion or reverse insertion. If it is forward insertion, the host uses CC1 to communicate with the equipment, and reverse insertion uses CC2. It can be seen that CC uses single line protocol. When DP function is turned on, SBU line is incarnated as aux in DP protocol_ P/AUX_ N differential line (its polarity can be modified according to the forward and reverse insertion direction) is responsible for transmitting DPCD, EDID and other key information of the equipment .

Usb type-c socket front view

View of usb-type-c plug outlet

2. Technical characteristics

On January 7, 2013, the USB3.0 Promotion Organization announced at the consumer electronics show that the first batch of devices with a transmission rate of 10Gb / s will be available in 2014. The USB interface of such products adopts the usb3.1 standard, i.e. type-C interface. The size of type-C interface socket end is about 8.3mmx2.5m, slim design; Support the "positive and negative plug-in" function that can be inserted from both positive and negative sides, and can withstand 10000 times of repeated plug-in; The standard specification cable equipped with type-C connector can pass 3A current, and also supports "USB PD" with USB power supply capacity, which can provide up to 100W power.

3. Type difference

Type-a is the most extensive interface standard in computer and electronic accessories. It is mostly used for mouse, USB flash disk and data line, and its volume is also the largest.

Type-B is generally used for external USB devices such as printers, scanners and USBhub.

Type-C has a much smaller volume than type-A and type-B. it is the latest USB interface appearance standard. This interface has no difference between positive and negative directions and can be plugged in and out at will.

4. Main characteristics

For the needs of data exchange, t electronic devices provide USB interfaces, whether PC, tablet point, mobile phone or even display device. Almost without exception, there is a USB interface. However, due to the limitation of technical standards, the USB plug has "directionality". If the direction is wrong during insertion, either it can't be inserted, or the interface or connector is damaged. In this case, apple designed the lightning [4] interface for its device. Since it can be inserted in both directions, users don't have to worry about the wrong insertion. In addition to Apple devices, the T industry has also introduced a similar interface standard: USB type-C. 

The trend of USB type-C was first led by apple. The advent of the new MacBook will USB type-c. This powerful technology has been brought into our vision. USB type-C is an interface specification, which is composed of type-C plug and type-C socket. Among various mobile devices and PCs, type-C has become the most promising data interface. With the gradual maturity of tpe-c technology, various newly launched electronic products in 2017 also chose to configure full type-C interface .

In fact, the most intuitive advantage of type-C is that it allows you to completely get rid of the trouble of inserting wires. Its innate excellent positive and negative pluggable interface design will no longer cause component damage caused by wrong insertion or mistakes. More importantly, the type-C interface has strong compatibility, so it has become a standardized interface that can connect PCs, game consoles, smartphones, storage devices and all electronic devices, and realize the unification of data transmission and power supply. For example, two display devices are closely combined through a type-C line.

In addition, type-C also supports the usb3.1 standard. The maximum power supply of the standard is 100W, and the voltage and current will be increased; The coding consumption is reduced from 20% of 3.0 to 3%. In other words, users can quickly transmit data and video through type-C, or charge faster. The standard also allows users to charge other devices with their mobile phones. For the display, when using type-C for data transmission, there is no need to use another power cord to power the display, which solves the problem of messy desktop wires. Even the relatively high-end HDMI and DP interfaces can not be used.

5 .Standard agreement

In September 2021, the usb-if Organization released the latest USB type-C interface and cable v2.1 standard protocol, and the power supply capacity was increased from 100W to 240W. In the future, the game book does not even need a separate power adapter.

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