What does the dvi connector look like? Interfaces
The standard provides simultaneous transmission of visual and audio information over a single cable; it is designed for television and cinema, but PC users can also use it to output video data using an HDMI connector.
HDMI is the latest attempt to standardize a universal connection for digital audio and video applications. It immediately received strong support from the giants of the electronics industry (the group of companies developing the standard includes companies such as Sony, Toshiba, Hitachi, Panasonic, Thomson, Philips and Silicon Image), and most modern devices output high resolution has at least one such connector. HDMI allows you to transmit copy-protected sound and image in digital format over one cable, the standard of the first version is based on bandwidth 5 Gb/s, and HDMI 1.3 expanded this limit to 10.2 Gb/s.
HDMI 1.3 is the latest standard specification with increased interface bandwidth, increased clock frequency up to 340 MHz, which allows you to connect high-resolution displays that support more colors (formats with color depths up to 48-bit). New version The specification also defines support for new Dolby standards for transmitting compressed audio without loss of quality. In addition, other innovations appeared; specification 1.3 described a new connector, smaller in size compared to the original.
In principle, the presence of an HDMI connector on a video card is completely optional; it can be successfully replaced by an adapter from DVI to HDMI. It is simple and therefore included with most modern video cards. Moreover, on video cards of the HDMI series, the connector is in demand primarily on mid- and low-level cards, which are installed in small and quiet barebones used as media centers. Because of the built-in audio, the Radeon HD 2400 and HD 2600 graphics cards have a definite advantage for builders of such multimedia centers.
Based on materials from the company's website iXBT.com
To transmit video signal to digital form A DVI (digital visual interface) connector is used. It was created when video media appeared in digital format - DVDs, and when it was necessary to transfer video from a computer to a monitor. The then existing methods of transmission analog signal did not allow achieving high picture quality, because it is physically impossible to transmit a high-resolution analog signal over a distance.
Video distortion can always occur in a communication channel, this is especially noticeable at high frequencies, and HD quality precisely implies the presence of high frequencies in the signal spectrum. To avoid these distortions, we tried to switch to a digital signal and abandon analog when processing and transmitting video from the media to the display device. Then, in the late 90s, several companies joined forces to create digital interface transmitting video data, excluding DAC (digital-to-analog) and ADC (analog-to-digital) converters from the path. The result of their work was the creation of the video signal transmission format - DVI.
Appearance of dvi connector:
View of the dvi connector inside:
Basic parameters of the dvi interface
This type of connection transmits information about the main components of the RGB signal (red, green, blue). Each component uses a separate twisted pair in the DVI cable, and there is a separate twisted pair cable for transmitting synchronization signals. It turns out that the DVI cable consists of four twisted pairs. A twisted pair connection allows you to use the principle of differential data transmission, when the interference has a different phase in each conductor and is subtracted at the receiver, but this technical features and it is not necessary to know them. Each color component is allocated 8 bits, and, in general, 24 bits of information are transmitted to each pixel. The maximum data transfer rate reaches 4.95 Gbps, at this speed you can transmit a signal with a resolution of 2.6 megapixels at a frame rate of 60 Hz. An HDTV signal, whose resolution is 1980x1080, has a resolution of slightly more than 2 megapixels, so it turns out that a high-resolution signal of 1980x1080 at 60 Hz can be transmitted through the DVI connector. There is only a limit on the cable length. It is believed that a high-resolution signal can be transmitted with a cable up to 5 meters long, otherwise distortion may occur in the image. When transmitting a signal with a lower resolution, it is permissible to increase the length of the DVI cable. It is also possible to use intermediate amplifiers if a larger length is still needed to transmit the video signal.
For greater compatibility, the DVI connector was made to support an analog signal. This is how three types of DVI connectors appeared:
- 1) DVI-D transmits only digital signal;
- 2) DVI-A transmits only analog signal;
- 3) DVI-I is used to transmit both digital and analog signals.
The connector itself is the same for all three types, so they are completely compatible, only they have a difference in the connected contacts in the connector.
There are also two data transfer modes: single link (single mode), dual link (double mode). Their main difference is in the supported frequencies. If in single mode the maximum signal can be 165 MHz, then in dual mode the limitation is imposed by the physical characteristics of the cable. This suggests that DVI Dual Link cables can transmit signals with higher resolution and over longer distances. That is, if, when using a single link cable, there is interference in the image of the LCD TV in the form of colored dots, then you can try replacing it with a dual link. Structurally, a dual mode DVI cable is distinguished by the use of double twisted pairs to transmit color components.
Features of the dvi connector
To implement such speeds, a special TMDS coding method. And in any DVI connection, a TMDS transmitter is used on the transmitting side for encoding, and the RGB signal is restored on the receiving side.
Additionally can be used in DVI interface DDC channel (Display Data Channel), which provides the source processor with EDID display information. This information provides details about the display device and includes information about the brand, model number, serial number, release date, screen resolution, screen size. Depending on this information, the source will produce a signal with the required resolution and screen proportions. If the source refuses to provide such information, it may block the TMDS channel.
Just like HDMI, DVI interface supports HDCP content protection system. Such a protection system is called intelligent protection and it is so called because of its implementation and the ability to install different levels protection depending on different cases, so such protection does not block normal data exchange (for example, when copying). It is implemented on the principle of exchanging passwords with all devices connected via DVI.
Only the image is transmitted through the DVI connector, and the sound will have to be transmitted through additional channels. Some video cards have the ability to transmit audio via a DVI cable, but special adapters are used for this, and this feature is additionally implemented in the video card itself. And then it is no longer a pure DVI interface. With a normal connection, audio needs to be transmitted additionally.
Types of DVI connectors and their technical characteristics
Many people have the problem of correctly identifying and selecting the necessary adapter for a video card or monitor. To make this task easier, we present to your attention a table of differences indicating the type of DVI connectors, as well as information about their technical characteristics.
Types of DVI
DVI-A is analog transmission only.
DVI-I - analog and digital transmission.
DVI-D is digital transmission only.
Video cards with DVI-A do not support monitors that comply with the DVI-D standard.
A video card with DVI-I can be connected to a DVI-D monitor (with a cable with two DVI-D-male connectors).
A DVI-I to VGA adapter exists.
There is no DVI-D to VGA adapter with video transmission function, only special converters that have a high cost (from 35 USD). There are DVI-VGA technology adapters on sale that serve other purposes and are not suitable for video signal conversion.
Specifications
The data format used in DVI is based on the PanelLink format serial transmission data developed by Silicon Image. Uses technology for high-speed transmission of digital streams TMDS (Transition Minimized Differential Signaling, differential transmission of signals with minimization of level differences) - three channels transmitting video streams and additional data, with a throughput of up to 3.4 Gbit/s per channel.
The maximum cable length is not specified in the DVI specification because it depends on the amount of information being transferred. The 10.5 meter cable can be used to transmit images with a resolution of up to 1920 x 1200 pixels. Using a cable 15 meters long it will be possible to transmit an image in normal quality with a resolution of 1280 x 1024 pixels. To amplify the signal when transmitting over long cables, special devices are used. When using them, the cable length can be increased to 61 meters (in the case of using an amplifier with its own power supply).
Types of DVI connectors
Single link DVI uses four twisted pair wires (red, green, blue, and clock), providing the ability to transmit 24 bits per pixel. With it, the maximum possible resolution of 1920x1200 (60 Hz) or 1920x1080 (75 Hz) can be achieved.
Dual link DVI doubles the bandwidth and allows for screen resolutions of 2560x1600 and 2048x1536. Therefore, for the largest LCD monitors with high resolution, such as 30" models, you definitely need a video card with a two-channel DVI-D Dual-Link output. If the monitor has a maximum screen resolution of 1280x1024, then connecting it with a dual link cable does not make sense, because To. this cable Designed for monitors with higher resolution.
A source of information -
We select the required plug for the appropriate connector. What types of cables do manufacturers offer? "HDMI,DVI,VGA,DisplayPort" and which interface is optimal for connecting a monitor.
Previously, to connect a monitor to a computer, only an analog interface was used VGA. Modern devices have connectors "HDMI,DVI,VGA,DisplayPort". Let's see what advantages and disadvantages each of the interfaces has.
With the development of new technologies for flat-panel monitors, the connector capabilities have become insufficient VGA. To achieve the highest image quality, it is necessary to use a digital standard such as DVI. Home entertainment device manufacturers have created a standard HDMI, which became the digital successor to the analog Scan connector. Somewhat later, VESA (Video Electronics Standards Association) developed DisplayPort.
Main interfaces for connecting monitors.
■ VGA. The first connection standard, still in use today, was developed in 1987 by the then leading computer manufacturer IBM for its PS/2 series PCs. VGA is an abbreviation for Video Graphics Array (an array of pixels), at one time this was the name of the video card in PS/2 computers, the resolution of which was 640x480 pixels (the combination “VGA resolution” often found in technical literature means exactly this value).
An analog data transmission system with increasing resolution only worsens the picture quality. Therefore, in modern computers the digital interface is the standard.
. ■ DVI. This abbreviation is oz-naHaeTDigital Visual Interface - digital video interface. It transmits the video signal in digital format while maintaining high image quality.
DVI is backwards compatible: Almost all computers have a DVI-I connector, which is capable of transmitting both digital video data and a VGA signal.
Inexpensive video cards are equipped with a DVI output in the Single Link modification (single-channel solution). Maximum resolution in this case it is 1920x 1080 pix. (Full HD). More expensive video card models have a two-channel DVI (Dual Link) interface. They can be connected to monitors with a resolution of up to 2560x1600 pix.
The DVI connector is large enough that Apple has developed a Mini DVI interface for its laptops. Using the adapter, you can connect devices with Mini DVI to monitors equipped with a DVI connector.
connection interfaces
■ HDMI. The abbreviation HDMI stands for High Definition Multimedia Interface, that is, a high-definition multimedia interface. In modern home entertainment devices such as flat-screen TVs and Blu-ray players, HDMI is the standard connection interface.
As with DVI, the signal is transmitted in a digital format, which means the original quality is preserved. Together with HDMI, HDCP (High Bandwidth Digital Content Protection) protection technology was developed, which prevents the creation exact copies, for example, video materials.
The first devices with HDMI support appeared at the end of 2003. Since then, the standard has been modified several times, in particular, support for new audio and video formats has been added (see table above).
For miniature models of equipment there is a Mini HDMI interface; An appropriate HDMI/Mini HMDI cable is included with many devices.
■ DisplayPort(DP). A new type of digital interface for connecting video cards with display devices is intended to replace DVI. The current version of the standard 1.2 allows you to connect multiple monitors when they are daisy-chained into one chain. However, currently there are not many devices with a DP port. As a direct competitor to HDMI, this interface has a significant advantage from the point of view of manufacturers: it does not require licensing fees. While for each device with HDMI you have to pay four American cents. If the connector on a computer or laptop is marked “DP++”, this indicates that the adapter can be used to connect monitors with DVI and HDMI interfaces.
To ensure that there is enough space on the back of modern video cards for connectors for other purposes, a smaller version of the DP interface was developed. For example, video cards Radeon series HD6800 contain up to six Mini DP ports.
HDMI,DVI,VGA,DisplayPort
Which of these standards will be most widely adopted? HDMI has a very high chance of success, since most devices have this interface. However, there is a new trump card in the deck of Asian manufacturers: according to official data, the Digital Interactive Interface for Video and Audio (DiiVA) provides a throughput of 13.5 Gbps (DP: 21.6; HDMI: 10.21. In addition, as the companies promise, the maximum cable length between devices, such as a Blu-ray player and a TV, will be up to 25 m. There is no information yet on what the DiiVA interface looks like.
Transfer video via USB
Two years ago it became possible to connect monitors via USB using DisplayLink adapters. However, due to the low (480 Mbps) bandwidth, the USB 2.0 connection is not suitable for video transmission. Another thing - latest version USB standard (3.0), providing data transfer speeds up to 5 Gbit/s.
An adapter from DisplayLink allows you to connect monitors directly to a computer's USB port.
How to connect a computer and a monitor with different interfaces.
Thanks to adapters, there are many connection options (see table below).
Common adapters, such as DVI-I/VGA, are quite reasonably priced. So-called converters that convert the digital DisplayPort output signal into an analog VGA signal are much more expensive.
However, for example, when connecting a TV with an HDMI interface to the DVI connector, there is almost always no sound.
Is it possible to combine devices with different HDMI versions?
With this combination, only the functions of the earlier version of the corresponding interface will be available. For example, if a video card with HDMI 1.2 is connected to a 3D TV that supports HDMI 1.4, then 3D games will only be displayed in 2D format.
Advice. Installing a new driver allows you to add support for HDMI 1.4 in some video cards based on NVIDIA chips, for example GeForce GTX 460.
What connectors provide best quality Images?
Testing has shown that the analog VGA interface provides the worst image quality, especially when transmitting signals with a resolution of more than 1024x768 pix. Even 17-inch monitors support this resolution today. Owners of monitors with a larger diagonal and a resolution of 1920x1080 pixel are strongly recommended to use DVI, HDMI or DP.
How to connect a monitor to a laptop?
Most laptops are equipped with connectors for connecting external monitors. First, connect the monitor to the laptop. After that, using the buttons Ш and KPI, you can switch between the following modes.
■ Using an external monitor as the main one. The laptop display turns off and the image is displayed only on the connected external monitor. The best option for movie buffs and gamers.
Clone mode. External monitor and laptop display show the same image
■ Practical for presentations and seminars.
■ Multi-screen mode. Allows you to increase the size of the Worker Windows desktop through the use of multiple monitors. It is very convenient, for example, when typing text in Word, to have email messages in front of your eyes.
Will it be possible to connect the TV to the computer?
IN modern computers and laptops do not have analog video interfaces such as S-Video or a composite connector. Therefore, you definitely won’t be able to connect an old CRT TV. However, the vast majority of flat-panel models are equipped with DVI or HDMI interfaces, which means connecting them to a computer is not difficult.
Netbooks, as a rule, only have a VGA output, and only those TVs that have a VGA input can be connected to them.
Is it possible to connect a monitor via USB
For traditional monitors this is only possible using an optional DisplayLink adapter. However, there are also models on sale that connect directly to a computer’s USB port - for example, Samsung SyncMaster 940 UX.
What is the maximum monitor cable length?
Cable capabilities depend on the connection type. When using DVI, the connection length can reach 10 m, but in the case of HDMI and VGA it should not exceed 5 m. To achieve maximum transfer speed.
What should you pay attention to when purchasing a video cable?
To those located nearby electronic devices did not affect the quality of the transmitted signal, purchase only well-shielded cables. When using a low-quality cable, other devices may cause interference and in some cases even reduce the data transfer rate. As a result, the screen will display a choppy image or an aliasing effect will appear. Gold-plated contacts prevent corrosion of the plugs due to high air humidity. In addition, the gold-plated contacts used in modern cables reduce the resistance between the connector and the plug, which improves transmission quality. But as you can see from practice: you can forget about all this, gold-plated contacts and other nonsense, with cheap cables made in China, namely, they are supplied complete with monitors and video cards. And they cope with their responsibilities very well.
For reference: once somewhere they gathered music lovers to test cables. There were both gold-plated and platinum contacts, from $1000 per cord and much more. Well, the ratings were given for sound quality. To determine the winner, the competition was held naturally in the dark, the manufacturer was not visible. Well, one of the organizers came up with the idea of sending a signal through an ordinary iron crowbar (which is used to hammer the ground). And what do YOU think, he took one of the prizes.
And music lovers spent a long time explaining what crystal clear sound comes through this cool cable. So turn on your head, otherwise I saw the guys have a cable DVI at a price higher than the video card and monitor combined.
