The first category: digital/analog signal interface HDMI interface, DVI interface, VGA interface, S-Video interface and RCA interface.
1, HDMI interface
The full name of HDMI in English is "high-definition multimedia", and in Chinese it means high-definition multimedia interface. Mainly used for high-end high-definition projectors, and a few low-end entertainment projectors are also equipped with HDMI interface.
HDMI can provide data transmission bandwidth up to 5Gbps, and can transmit uncompressed audio signals and high-resolution video signals. At the same time, signal transmission does not need digital-to-analog or analog-to-digital conversion, and can only transmit high-quality audio-visual signals.
2.DVI interface
DVI interface, that is, digital video interface, is used to replace VGA analog interface. Because the transmission is a digital signal, the digital image information does not need any conversion, so the signal is not attenuated, and the color is purer and more realistic. At the same time, the single channel DVI can support the resolution of 1920× 1200 at the highest, and the dual channel DVI can support the resolution of 2560× 1600 at the highest. However, in the field of projectors, the penetration rate of DVI is very low, so in many cases, users connect computers and projectors with HDMI high-definition interface.
3.VGA interface
VGA interface is divided into input and output interface, which is commonly called D-sub interface or PC interface. It is the most common and commonly used interface on the projector, mainly used to connect computer equipment. The asymmetric distribution of 15Pin connection mode can only transmit analog signals. Its working principle: the image (frame) signal stored in digital format in video memory is analog modulated into analog high-frequency signal in RAMDAC, and then output to projector for imaging, so VGA signal is at the input end), so it does not need to be converted by matrix decoding circuit like other video signals.
4, S video
The English full name of S-Video is Separate Video, also known as the two-component video interface. Separating video means transmitting video signals separately, that is, separating chroma signal C and brightness signal Y on the basis of AV interface, and then transmitting them in different channels.
The Chinese name of standard S-Video interface and plug S-Video is generally called S terminal, including 4-core (no sound output), 5-core, 6-core, 7-core, 8-core and 9-core (which can provide 6-channel signal output). Generally, it will appear on the projector. If it is not carefully distinguished, it will be mistaken for the PS2 interface of the computer.
5.RCA interface
RCA interface is commonly known as AV interface or AV terminal, and almost all projectors, televisions and playback devices on the market are equipped with this interface. However, since entering the high-definition era, the utilization rate of AV interface has been greatly reduced. AV interface is an early interface, which is composed of yellow, white and red lines. The yellow line is the video transmission line, and the white and red lines are responsible for the sound transmission of the left and right channels.
The second category: data interface USB interface and SD/TF interface.
1, USB interface
As a data reading interface, USB interface has been recognized by everyone. The latest USB read-only function, in addition to common jpg pictures and TXT documents, can already support the direct playback of Microsoft Office software and PDF files, even videos like WMV. Basically, you can complete the basic business slide presentation independently without the restriction of the computer, but the compatibility needs to be improved.
2. SD /TF interface
TF, also known as T-Flash card, full name: TransFLash, also known as Micro SD, is an ultra-small card (11*1mm), which is about 1/4 of SD card, and can be considered as the smallest memory card at present. For such a memory card, some projectors are basically equipped with TF interface, which is convenient for using TF card.
The third category: network interface.
Network interface refers to various interfaces of network devices. When in use, you can connect the network with the crystal head network cable. There are two main functions: one is to realize networked centralized management through special software, which can control thousands of projectors at the same time; The second is the network projection function. After the projector is connected to the network, it can directly access the IP address of the designated computer and directly project the computer picture through the network.
The fourth category: component interface Y interface, Cb/Pd interface, Cr/Pr interface.
The component interface, also known as the color difference video interface, transmits brightness information and color information of the video signal respectively, so that the video signal includes a brightness signal and two separately transmitted color difference signals. On the projector module interface, it mainly consists of three interfaces: Y interface, Cb/Pd interface and Cr/Pr interface.
Category 5: audio interface 3.5mm audio interface, RCA (audio).
Audio interfaces can be divided into two types: input and output. The former uses the projector's built-in speaker to make sound, while the latter transmits the audio information input by HDMI to the external speaker. Generally speaking, the audio interface usually adopts Lotus interface or 3.5mm interface.
3.5mm audio interface is the most common specification now, which is basically used in mobile phones, mp3 players, sound cards and so on. The standard RCA data cable, yellow as video cable, white and red as left and right channel lines RCA (audio) is generally integrated with the previously introduced RCA (video) line. The same lotus interface is adopted, and one coaxial cable is used for the left and right channels to complete audio transmission.
References:
Baidu Encyclopedia-Projector Input Interface