For example, a cable that only supports 5A charging and does not support data transmission only needs to be connected to the pins of VBUS+GND (transmitting 5A current) and CC+VCONN (for type-c communication) in the USB type-c interface.

If a USB 2.0 speed data transmission function is required, an additional D+/D-pin is required, and the actual number of outgoing lines needs to be 6. This standard cable does not require high interface requirements, and only 4-layer PCB material made of ordinary FR4 material can meet the 5A current transmission level.

But if it is a fully functional cable, it is necessary to use TX1+/TX1-, RX1+/RX1-, TX2+/TX2-, RX2+/RX2-, and sideband signal SBU1/SBU2 corresponding to USB 3.1 on top of the former. The actual number of outgoing lines is at least 16.

In addition, this type of interface also requires the selection of high-frequency and high-performance 6-layer PCB boards. The routing of high-speed signal lines should be very careful, as high-speed rates exceeding 5Gbps have entered the microwave field. Transmission of such high rates through connectors and cables must consider the distortion caused by channel discontinuity. In order to maintain the distortion level at a controllable level, the cable needs to pass through impedance, delay, time delay A series of testing items such as attenuation and crosstalk.

The USB type-c cable material can achieve different functions and performance by connecting different numbers of pins in the type-c interface and matching them with corresponding E-Marker chips, but this is not enough. Because the transmission of electricity, data, and audio and video ultimately needs to be implemented on the data and power cores inside the cables, the materials used in the latter will directly determine the transmission quality of various signals.

For example, truly exquisite cables require the addition of steel sleeves and hard sealing glue for protection and insulation inside, metal shielding mesh and shielding aluminum foil inside the cable body to prevent signal interference, and the flexibility of the cable is increased by filling with Teflon insulators, Keff wires, anti pulling wires, and cotton wires. The higher the grade, the thicker the diameter of the cable, but after optimization through the above methods, its bending resistance can be significantly improved, effectively resisting daily wear and tear.

And some cables that are not particular about are either very thin and feel extremely poor quality to the touch, or they are very hard and afraid of breaking when bent and stored.

Let's take a well-known data cable brand as an example to see its internal material specifications for USB type-c cables of different specifications. Taking a cable that supports 5A and USB 2.0 data transmission as an example, it only requires 4 sets of wire cores internally and uses ordinary thick tinned copper cores.

For cables that support 5A, 10Gbps data transmission, and audio and video output, 10 tin plated copper cores and 8 silver plated copper cores need to be designed. If it is a lightning wire that supports 40Gbps, it is also necessary to thicken the silver plated copper core.

For cables that support audio and video output, in order to ensure signal stability, coaxial cable structures are mostly needed. Each cable includes an independent insulation protection layer, outer conductor shielding layer, insulation layer, and inner conductor (Figure 21).

However, when a signal is transmitted within a coaxial cable, its attenuation is related to the transmission distance and the frequency of the signal itself. For high-frequency signals, the farther the transmission distance, the greater the signal attenuation. Therefore, the length of the most high-end lightning wire generally does not exceed 0.5 meters, and exceeding 0.5 meters requires additional chips to amplify the signal, which is extremely expensive.

The source of the confusion of usb type-c cable has taken down almost all electronic devices except iPhone, but the confusion of the matched cable specifications is also dazzling, because different types of products have different requirements for it. For example, the USB type-c interface on Bluetooth headphones only needs to be able to charge 1A, and a mobile power supply that supports 65W PD fast charging only needs 3A. The USB type-c interface on the Portable storage device is only responsible for data transmission. The low-cost cables on the market are actually prepared for the above devices, which is enough.

Relatively speaking, the USB type-C interface on laptops and mobile phones has higher expectations for cables, but this also depends on the specific model.

Taking laptops as an example, many mid to low end products only support 5Gbps data transmission with USB type-C interfaces. Some support 10Gbps data transmission, while others also support PD protocol charging and DP video output functions in addition to data transmission. This type of USB type-C is commonly referred to as "fully functional".

The data-driven USB type-c interface can be paired with a pure USB hub to expand to more USB, network cable interfaces, or card readers

The full-featured usb type-c interface can be used with high-end Docking station, including HDMI and charging interfaces. On high-end notebooks, we can also see the Emperor class Thunderbolt 3/4 interface. With the popularity of the 11th generation Core notebooks, Thunderbolt interface has gradually moved down to the mid market, and many 11th generation Core thin and light notebooks have been equipped with Thunderbolt 4 as standard.

The lightning interface can be used with an external Docking station or a 5K~8K resolution display. In the mobile phone field, the USB type-c interface of Huawei Mate/P series and Nut R2 as the representative products supports video output, which is equivalent to a full function type. It can also be used with the Docking station in the above figure to output the painting surface to the display end and operate with the keyboard and mouse. Unfortunately, the USB type-c interface of more models in the mobile phone industry only supports 18W PD charging (excluding private fast charging protocol) and USB 2.0 data transmission capability.

From an economic perspective, we should match sufficient cables based on the functionality of the USB type-C interface on the specific device at hand. However, from a practical perspective, the author recommends purchasing at least one fully functional USB type-c cable that supports 5A, 10Gbps, and DP video (4K) output to meet the charging, data transmission, and external display needs of various electronic products at home. No matter what device, it can be used immediately without affecting performance.

Source: Computer enthusiasts