Projector interface, future development trend analysis

With the rapid development of digital technology, projectors have become the standard configuration of multimedia classrooms, multi-functional conference halls, and large and medium-sized clubs and other demonstration venues. They have a tendency to completely replace traditional blackboards and whiteboards. At present, most projectors can automatically recognize the input signal source, and at the same time automatically switch and automatically change settings according to the type of the signal source. The connection technology of the projector will develop toward more and more humanization. In addition, wirelessly connected projectors are also a trend for the future development of projectors.

Since the projector needs to meet classroom teaching, conference presentation, home theater, and mobile office, it will inevitably need to provide a variety of different interfaces, resulting in an interface on the back of a projector with a small area, and the interface is actually more than the server. Coupled with the included power supply cable, signal cable, signal control cable, video cable, remote control and other accessories, it is certain that the users of the projector will not be able to find the North. So what are the interfaces and connection lines of the projector so much? what is it used for? How to connect?

The projector's interface can be roughly divided into two kinds: Analog signal interface and digital signal interface, some models also provide audio input and output terminals. The analog signal interfaces include: composite video signal input interface (CVBS), S-Video input interface, European standard video interface (SCART), color difference input interface, RGBHV input interface, and VGA-PC 15-pin VGA input interface.

The composite video signal input interface (CVBS) is mainly used to input television signals. The S-Video input interface is a video interface developed with the advent of video recorders and is now widely used in video recorders and video players. The European standard video interface (SCART) is used to transmit RGB signals. The color difference input is used to transmit a separate image of the luminance signal and the color difference signal, which is divided into a progressive scan and an interlaced scan.

The signal transmitted by RGBHV is equivalent to VGA, but its 5RCA socket is usually used in the field of dedicated display. The 15-pin VGA input connector of the VGA-PC is one of the most common interfaces used to connect the computer's video output.

Digital signal interface includes: USB interface, IEEE1394 interface, DVI interface and HDMI interface. The USB interface is usually used to transfer picture files, but not to transmit video files. The IEEE1394 interface can be used to transfer MPEG2 digital images. However, due to the relatively complicated and expensive technology, projectors equipped with IEEE1394 interfaces are also relatively rare.

The DVI interface can transmit video images up to 2048*1536@75Hz, so it is widely used in projectors and plasma displays. Most mid to high-end projectors on the market are equipped with DVI digital interfaces, but recently some new products use HDMI interfaces instead. The DVI interface. The HDMI interface is based on the DVI interface, adding digital audio input, thus becoming a dedicated multimedia information interface, and supports 1920 * 1080 DPI high-definition digital signals, HDMI is expected to become the standard interface for future video equipment.

The closest contacts to the projector are computers, including desktop computers and laptops. In the cable that comes with the projector, both the VGA signal cable and the signal control cable are used to connect directly to the computer. The VGA signal cable is connected to the computer's video output connector and the projector's VGA input connector. The signal control cable is connected to the projector's main control port and the computer's COM port.

In the daily application, in order to facilitate the screen switching between the computer and the projector, a VGA Multinier distributor is usually used for relay connection, so that two VGA signals can be derived from the distributor, and one signal is transmitted to the projector for display. The other signal is transmitted to the display, and the presenter only needs to operate through the computer's display without having to stand in front of the projection screen to view the projected content for explanation.

The average user will set the 17-inch CRT display to a resolution and refresh rate of 1024*768@85 or higher, but when using a video splitter to connect both the monitor and the projector, attention should be paid to the resolution and refresh rate. set up. When the projector displays a hint that the input signal is out of range, the resolution and refresh rate of the graphics card should be appropriately reduced, otherwise the projector cannot recognize the image. In addition, the projector must also be “satisfactory” with the computer to obtain the best projection effect. For example, if the resolution of the projector is relatively high, it must be matched with a computer that supports high resolution.

In addition to the desktop computer, the projector is more connected to the laptop, especially after the emergence of the portable projector, the combination of laptop + projector has become another choice for mobile workers. Notebooks generally provide D-Sub 15-pin VGA output interface, plus their own LCD display, so there is no need to use video splitter connection, but need to pay attention to the output mode, notebook computers generally provide three output modes: LCD screen only Output, only the VGA port output and LCD screen and VGA port output at the same time, the default state is only the LCD output, so when you connect the projector, you need to change the notebook output mode.

With the continuous maturity of projection technology, projectors are becoming more and more user-friendly. “Plug and Play” makes the operation of the projector very convenient. At present, most projectors can automatically recognize the input signal source, and at the same time automatically switch and automatically change settings according to the type of the signal source. The connection technology of the projector will develop toward more and more humanization. In addition, wirelessly connected projectors are also a trend for the future development of projectors.