In modern display devices, there are many different interfaces and cables for transmitting video and audio signals. These interfaces and cables have their own characteristics and advantages and disadvantages, and are also suitable for different scenarios and needs. This article will introduce six common interfaces and cables: VGA cable, DVI cable, HDMI cable, DP cable, SDI cable and Thunderbolt 4 cable.
VGA cable
VGA (Video Graphics Array) is an ana-log signal interface that first appeared in the era of CRT (cathode ray tube) monitors. VGA uses a 15-pin pin structure to transmit component (RGB) and synchronization signals. VGA interfaces are commonly found in old graphics cards, notebooks and projectors.
The advantage of the VGA interface is good compatibility and can adapt to different resolutions. The disadvantage of the VGA interface is large signal loss, blurred image quality, and supports up to 1080p resolution. At high resolution, font blur, image jitter and tailing will occur. Since VGA outputs and transmits ana-log signals, while computer graphics cards generate digital signals and monitors also use digital signals, using the VGA video interface is equivalent to undergoing a digital-to-analog conversion and an ana-log-to-digital conversion, resulting in signal degradation.
The VGA interface has been gradually eliminated, and some new monitors no longer have a VGA interface. If you want to use the VGA interface, you need to buy an adapter or converter.
DVI cable
DVI (Digital Visual Interface) is a digital signal interface. Later, the white DVI interface appeared. When we encounter different interfaces, we have to buy an adapter for conversion. Later, there were interfaces such as HDMI, and now there are DP and USB Type-C interfaces. So, with so many interfaces, what are the differences, and which one should we use?
There are many types of DVI interfaces. According to the different transmission signals, they can be divided into DVI-A (ana-log signal), DVI-D (digital signal) and DVI-I (ana-log + digital signal). According to the different bandwidths, they can be divided into single channel (Single Link) and dual channel (Dual Link). Their interface shapes are different. If the interfaces do not match, they cannot be inserted and used.
The DVI interface transmits digital signals and can transmit high-resolution video signals. DVI does not require conversion when connecting the computer graphics card and the monitor, so there is no signal loss. The advantages of the DVI interface are clear picture quality and support for high refresh rate. The disadvantage of the DVI interface is that it does not support audio transmission and requires an additional audio cable. With the popularity of new interfaces such as HDMI and DP, the DVI interface is gradually being eliminated.
HDMI cable
HDMI (High Definition Multimedia Interface) is a high-definition multimedia interface and is currently the most common connection cable. TVs, computers, and projectors all support it. The HDMI interface is a left-right symmetrical trapezoid that can transmit images and audio at the same time.
The HDMI interface has been upgraded many times and has now developed to the HDMI 2.1 standard, supporting 4K 120Hz and 8K 60Hz resolution and refresh rates, supporting high dynamic range imaging (HDR), and can be optimized for scenes or frames. It is backward compatible with older versions such as HDMI 2.0 and HDMI 1.4. The advantages of the HDMI interface are high popularity, good compatibility, support for audio transmission, and support for multiple protocols (such as EDID, HDCP, etc.). The disadvantages of the HDMI interface are limited length (generally no more than 15 meters), no support for variable refresh rate technology (such as FreeSync and G-Sync), and no support for daisy chain connection of multiple monitors.
DP cable
DP (Display Port) is a digital signal interface and a competitor of HDMI interface. In addition to HDMI interface, some graphics cards and monitors also have DP interface. DP interface is a rectangle with one corner missing, which can transmit images and audio at the same time.
DP interface has also been upgraded many times. The latest DP 1.4 version can transmit 10-bit 4K 120Hz video and 8K 60Hz video. DP1.4 is compatible with USB Type-C interface, which can transmit data while outputting images, and DP1.4 supports daisy chain connection of multiple monitors. The advantages of DP interface are high bandwidth, support for high resolution and high refresh rate, support for variable refresh rate technology (such as FreeSync and G-Sync), support for HDR and daisy chain. The disadvantages of DP interface are low popularity, incompatibility with old equipment, and limited length (generally no more than 3 meters).
SDI cable
SDI cable SDI (Serial Digital Interface) is a serial digital signal interface, mainly used for professional video equipment such as cameras, monitors, switchers, etc. The SDI interface is circular and uses coaxial cable to transmit signals. It can support long-distance (up to 300 meters) high-definition video transmission.
SDI interface has multiple standards. According to the transmission rate and resolution, it can be divided into SD-SDI (standard definition), HD-SDI (high definition), 3G-SDI (3Gbps), 6G-SDI (6Gbps) and 12G-SDI (12Gbps). Their interface shapes are the same, but they are not compatible. The advantages of the SDI interface are high stability, strong anti-interference ability, support for high-definition video and audio transmission, and support for multiple protocols (such as EDH, ANC, etc.). The disadvantages of the SDI interface are high cost, low popularity, and it is not suitable for ordinary consumers.
Thunderbolt 4 cable
Thunderbolt 4 is a high-speed data transmission interface and an upgraded version of Thunderbolt 3. Thunderbolt 4 adopts the appearance of USB Type-C and can transmit data, video, audio and power at the same time. Thunderbolt 4 is compatible with protocols such as USB4, USB3.2, USB2.0, DisplayPort1.4a and PCIe3.0, and is also backward compatible with Thunderbolt 3 and Thunderbolt 2.
The speed of Thunderbolt 4 is the same as Thunderbolt 3, both are 40Gbps, but Thunderbolt 4 has been improved in other aspects. For example, Thunderbolt 4 supports dual 4K or single 8K display output, supports power output up to 100W, supports active cables up to 10 meters or passive cables up to 2 meters, supports daisy chain connection of up to four Thunderbolt devices, supports security protection based on DMA (direct memory access), etc.
The advantages of Thunderbolt 4 are fast speed, powerful functions, good compatibility, and support for multiple protocols and devices. The disadvantages of Thunderbolt 4 are high cost and currently not many devices are supported. Thunderbolt 4 is mainly suitable for professional users who need high-speed data transmission and multi-function expansion, such as video editors, gamers, etc.
VGA cable, DVI cable, HDMI cable, DP cable, SDI cable and Thunderbolt 4 cable are six common display device connection cables. They have their own characteristics and advantages and disadvantages, and are suitable for different scenarios and needs.
