What does a dvi connector look like? Types of DVI connectors and their technical characteristics

Interfaces currently in widespread use:

VGA

DVI-D

DVI-I

HDMI

Legacy and exotic interfaces:

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From this article you will learn what a dvi connector is, types and features. You will also learn to distinguish this interface from others. This will help you replace cables if they fail, and you will also understand what equipment you can connect to each other.

Getting to know the interface

First, let's figure out what DVI is. The abbreviation hides the phrase “Digital Visual Interface”, which means “digital video interface”. Have you guessed the purpose of its use? He sends the digital recording to video equipment. Used to connect mainly plasma and LCD TVs.

Technical features

• The data format used in this interface is based on another - PanelLink, which involves sequential transfer of information.
• High-speed TMDS technology is used: three channels processing video streams at speeds of up to 3.4 Gbit per second for each of them.
• The maximum cable length has not been established, since it is determined by the arrays of transmitted information. For example, a 10.5 m wire is capable of converting a picture to 1920×1200 pixels, and a 15 m wire is capable of converting a picture to 1280×1024 pixels.

• There are two types of cable:

— Single link (single mode) assumes 4 twisted pairs s: 3 of them transmit RGB signals (green, red, blue) and the 4th one is for the sync signal. The wires process 24 bits per pixel. Thus, the maximum resolution is 1920x1200 (60 Hz) or 1920x1080 (75 Hz).

— In Dual (double), the parameters have increased by 2 times. Therefore, through it you can watch videos at 2560x1600 and 2048x1536 pixels.

History of appearance

The connector was released in 1999 by Digital Display Working Group. Previously, only the VGA interface was used, which provided 18-bit color and analogue conversion of information. With the increase in the diagonals of digital displays and the requirements for picture quality, naturally, VGA has become limited. This is how the world received DVI, which still holds its mark to this day.

Differences between DVI and VGA

What's the difference with VGA?

DVI has 17-29 pins, while its predecessor had 15.

VGA converts the signal 2 times, and DVI - 1. How is this? The image is sent to your computer by a video card, which itself is a digital device. Since the legacy interface is analog, it first converts the signal into the same type that it understands, and then outputs a number. As you understand, in the case of DVI this is not necessary.

• Due to lack of conversion new interface produces a better picture, but on a small monitor you are unlikely to see the difference.
• DVI assumes automatic image correction with the ability to change only brightness and saturation for ease of viewing, while VGA has to be fully configured.
• The quality of data transmission through an outdated interface may deteriorate due to external interference, which cannot be said about the new connector.

You may have heard about another, newer, digital interface - because now it is used, perhaps, more often than DVI. So that you don’t confuse them with each other, let’s look at the main differences:

• External design

DVI transmits only video, while HDMI also transmits 8-channel audio.

• The first one can work with both analog and digital signals, and the second one can work exclusively with digital signals.
• The modern interface is equipped with a built-in Ethernet channel with a speed of 100 Mbit, while DVI does not offer such a bonus.

There is also a difference in image quality.

DVI can only output images in Full HD (1920×1080), while HDMI can output 10K (10240×4320).

Types of DVI

You already know how not to confuse this interface with others. Now let’s look at how its varieties differ from each other:

• DVI-I. The additional letter means “integrated” (in our language - “united”). This type of connector provides analog and digital channels (Single Link version), which operate autonomously. Which one should be working at one time or another depends on the connected equipment. Dual Link mode provides 2 digital and 1 analog channels.
• DVI-D The last letter hides the word “digital”, which in Russian means “digital”. That is, in this type of interface there is no analog channel.

This type of connector is also available in two versions.

— Single Link has only one digital channel, which limits the resolution to 1920x1200 at 60Hz. It is also impossible to connect an analog monitor through it and implement nVidia technology 3D Vision.

— Dual Link involves 2 digital channels, which increases the capabilities to 2560x1600 at 60Hz. This interface allows you to watch 3D on a monitor.

• DVI-A. The additional letter carries the term "analog". Can you guess what this means even without translation? That's right, this is an analog interface, only in the form of DVI.

That's all.

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DVI (Digital Visual Interface, digital image interface) — connector developed Digital Display Working Group , as the first digital connector for liquid crystal ( LCD) panels. Since analog D—Sub was intended for CRT monitors, when the signal level changes, the brightness also changes, which for LCD monitor is not advisable. In addition, it has already begun to approach the threshold of throughput required for high resolutions. And the extra signal converter at the monitor input certainly didn’t improve the picture. Later, the problem of changing brightness for D-Sub decided, and the interface is still used in budget monitors in a single copy, or for compatibility with digital inputs.

Serial format is used for data transmission PanelLink, which uses T ransition M minimized D preferentialS ignaling (signal transmission with minimal signal changes). Supported 3 streams for data transfer at speeds up to to3.96 Gbps.

To achieve maximum speed transmission, it is necessary that the cable length does not exceed 1.5 meters. With increasing length, signal starts fade away, so when connecting over long distances you need to use special active amplifiers . Also, the signal transmission ability is highly dependent on wire quality, their resistance, etc.

Designations and types of DVI connectors:

• DVI-D- Supports digital transmission only

• DVI-A – supports analogue transmission only

• DVI-I – supports analog and digital transmission

The connector transmits 24's bit color in all resolutions, but when using Dual-link DVI on certain equipment, theoretically, it is possible to achieve 48 bit.

Maximum resolution for single channel mode ( Single-Link) DVI — 1920 X 1200 X 60Hz.

For two-channel ( Dual-Link) mode the maximum resolution is - 3,840 × 2,400 X 33 Hz, or 2,560 × 1,600 at standard 60 Hz.

Under any problems in displaying information via DVI, the main reasons may be:

• · Squeezing, twisting of the cable.

• · Poor contact or clogged contacts of the plug and plug.

• · Electromagnetic interference passing nearby cables high voltage, or the DVI cable is poorly shielded.

• · The resolution is too high and therefore there is not enough bandwidth.

To 2015 year it is planned to completely displace DVI new standard -

Probably every user of a personal computer or laptop has encountered issues with connecting a monitor or TV to it, as well as the quality of the resulting image. And if earlier getting a high-quality picture on the screen was quite problematic, today this problem does not exist at all. Of course, if your device has a DVI connector. This is what we will talk about, and also consider other existing interfaces for displaying images on the screen.

Types of connectors for displaying images on a computer monitor or screen

Until recently, everything personal computers had an exclusively analog connection to the monitor. To transfer images to it, a VGA (Video Graphics Adapter) interface with a D-Sub 15 connector was used. Experienced users still remember the blue plug and 15-pin socket. But, besides this, video cards also had other connectors designed to display images on a TV screen or other video device:

• RCA (Radio Corporation of America) - in our opinion, “tulip”. An analog connector designed to connect a video card to a TV, video player or VCR using a coaxial cable. Has the worst transmission characteristics and low resolution.
• S-Video (S-VHS) is a type of analog connector for transmitting a video signal to a TV, VCR or projector, dividing the data into three channels responsible for a separate base color. The quality of signal transmission is slightly better than “tulip”.
• Component connector - output to three separate “tulips”, used to output images to the projector.

All of these connectors were widely used until the late 1990s. Of course, there was no question of quality, since both televisions and monitors at that time had very low resolution. Now we can’t even imagine how it was possible to play computer games looking at a television screen with a cathode ray tube.

With the advent of the new century, thanks to the introduction of digital technologies in the development of video devices, RCA, S-VHS and component output began to be used less and less. The VGA interface lasted a little longer.

A little history

The operating principle of a conventional video card was that the digital image output from it had to be converted into an analog signal using a RAMDAC device - a digital-to-analog converter. Naturally, such conversion already deteriorated the image quality at the initial stage.

With the advent of digital screens, it became necessary to convert the analog signal at the output. Now monitors have also begun to be equipped with a special converter, which again could not but affect the image quality.

And here, in 1999, DVI appeared, seemingly out of nowhere, the latest digital video interface, thanks to which we can today enjoy the perfect picture on the screen.

The development of this interface device was carried out by a whole group of companies, which included Silicon Image, Digital Display Working Group and even Intel. The developers came to the conclusion that there is no need to convert a digital signal to analog, and then vice versa. It is enough to create a single interface, and the image in its original form will be displayed on the screen. And without the slightest loss of quality.

What is DVI

DVI stands for Digital Visual Interface. The essence of its work is that a special TMDS encoding protocol, also developed by Silicon Image, is used to transmit data. The method of transmitting a signal through a digital video interface is based on the sequential sending of information previously implemented by the protocol, with constant backward compatibility with analog VGA channel.

The DVI specification allows for a single TMDS connection to operate at up to 165 MHz and a transfer rate of 1.65 Gbps. This makes it possible to obtain an output image with a resolution of 1920x1080 with a maximum frequency of 60 Hz. But here it is possible to simultaneously use a second TMDS connection with the same frequency, which allows you to achieve a throughput of 2 Gbit/s.

Having such indicators, DVI left far behind other developments in this direction and began to be used on all digital devices without exception.

DVI for the average user

Without delving into the jungle of electronics, a digital video interface is just a special encoding device that has a corresponding connector on the video card. But how do you know that a computer or laptop has a digital output?

It's very simple. The connectors of video cards with a digital interface cannot be confused with others. They have a specific appearance and shape, different from other nests. In addition, the DVI connector is always white, which makes it stand out from the rest.

In order to connect a monitor, TV or projector to a video card, you simply plug in the plug of the desired wire and secure it using special hand-screwed bolts.

Resolution and scaling

However, neither digital coding nor special video card connectors have completely solved the problem of computer-monitor compatibility. A question arose about image scaling.

The fact is that all monitors, screens and televisions that already have a DVI connector are not capable of outputting a higher resolution than what is provided by their design. Therefore, it often happened that the video card produced a high-quality picture, and the monitor showed it to us only in a quality limited by its capabilities.

The developers caught on in time and began equipping all modern digital panels with special scaling devices.

Now, when we connect the DVI connector on the monitor to the corresponding output on the video card, the device instantly self-adjusts, choosing the optimal operating mode. We usually don’t pay any attention to this process and don’t try to control it.

Video cards and DVI support

The first video cards of the NVIDIA GeForce2 GTS series already had built-in TMDS transmitters. They are still widely used today in Titanium cards, being integrated into rendering devices. The disadvantage of built-in transmitters is their low clock frequency, which does not allow achieving high resolution. In other words, TMDS do not make the most of their advertised 165 MHz bandwidth. Therefore, we can say with confidence that NVIDIA at the initial stage failed to adequately implement the DVI standard in its video cards.

When video adapters began to be equipped with an external TMDS, working in parallel with the built-in one, the DVI interface was able to produce a resolution of 1920x1440, which exceeded all the expectations of the company's developers.

The Titanium GeForce GTX series had no problems at all. They effortlessly provide images with a resolution of 1600x1024.

ATI took a completely different path. All of its video cards that have DVI outputs also operate from integrated transmitters, but they are supplied complete with special DVI-VGA adapters that connect 5 analog DVI pins to VGA.

Maxtor specialists decided not to bother at all and came up with their own way out of the situation. The G550 series video cards are the only ones that have a dual DVI cable instead of two signal transmitters. This solution allowed the company to achieve a resolution of 1280x1024 pixels.

DVI connector: types

It's important to know that not all digital connectors are created equal. They have different specifications and designs. In ours with you everyday life The most common types of DVI connectors are:

• DVI-I SingleLink;
• DVI-I DualLink;
• DVI-D SingleLink;
• DVI-D DualLink;
• DVI-A.

DVI-I SingleLink connector

This connector is the most popular and in demand. It is used in all modern video cards and digital monitors. The letter I in the name means “integrated”. This DVI connector is special in its own way. The fact is that it has two combined transmission channels: digital and analog. In other words, this is a DVI+VGA connector. It has 24 digital pins and 5 analog pins.

Considering that these channels are independent of each other and cannot be used simultaneously, the device independently chooses which one to work with.

By the way, the first such integrated interfaces had separate DVI and VGA connectors.

DVI-I DualLink connector

DVI-I DualLink is also capable of transmitting an analog signal, but, unlike SingleLink, it has two digital channels. Why is this necessary? Firstly, to improve throughput, and secondly, it all comes down to resolution again, which is directly proportional to image quality. This option allows you to expand it to 1920x1080.

DVI-D SingleLink connector

DVI-D SingleLink connectors do not have any analog channels. The letter D informs the user that this is a digital interface only. It has one transmission channel and is also limited to a resolution of 1920x1080 pixels.

DVI-D DualLink connector

This connector has two data channels. Their simultaneous use makes it possible to obtain 2560x1600 pixels at a frequency of only 60 Hz. In addition, this solution allows some modern video cards, such as nVidia 3D Vision, to reproduce three-dimensional images on a monitor screen with a resolution of 1920x1080 with a refresh rate of 120 Hz.

DVI-A connector

In some sources, the concept of DVI-A is sometimes found - a digital connector for transmitting exclusively analog signal. In order not to mislead you, let us immediately indicate that in fact such an interface does not exist. DVI-A is just a special plug in cables and special adapters for connecting analog video devices to the DVI-I connector.

Digital connector: pinout

All of the listed connectors differ from each other in the location and number of contacts:

• DVI-I SingleLink - has 18 pins for digital channel and 5 for analog;
• DVI-I DualLink - 24 digital pins, 4 analog, 1 - ground;
• DVI-D SingleLink - 18 digital, 1 - ground;
• DVI-D DualLink - 24 digital, 1 - ground

The DVI-A connector also has its own unique pin arrangement. Its pinout consists of only 17 pins, including ground.

HDMI connector

A modern digital video interface also has other types of connecting communications. For example, the HDMI DVI connector is in no way inferior in popularity to the listed models. On the contrary, due to its compactness and the ability to transmit an audio signal along with digital video, it has become a mandatory accessory for all new TVs and monitors.

The abbreviation HDMI stands for High Definition Multimedia Interface, which means “high-definition multimedia interface.” It appeared for the first time in 2003 and since then has not lost any of its relevance. Every year new modifications appear with improved resolution and bandwidth.

Today, for example, HDMI makes it possible to transmit video and audio signals without loss of quality over a cable up to 10 meters long. The throughput is up to 10.2 Gb/s. Just a few years ago this figure did not exceed 5 Gb/s.

Support and development this standard The world's leading companies producing radio electronics are engaged in this: Toshiba, Panasonic, Sony, Philips, etc. Almost all video devices today manufactured by these manufacturers must have at least one HDMI connector.

DP connector

DP (DisplayPort) is the newest connector that replaced the HDMI multimedia interface. Possessing high throughput, minimal loss of quality during data transmission and compactness, it was designed to completely replace the DVI standard. But it turned out that not everything is so simple. Most modern monitors do not have the appropriate connectors, and changing their production system in a short time is impossible. In addition, not all manufacturers are particularly committed to this, which is why most video equipment is not equipped with the DisplayPort standard.

Mini connectors

Today, when computers are often replaced by more mobile devices: laptops, tablets and smartphones - using conventional connectors becomes not very convenient. Therefore, manufacturers such as Apple, for example, began to replace them with smaller analogues. First VGA became mini-VGA, then DVI became micro-DVI, and DisplayPort shrank to mini-DisplayPort.

DVI adapters

But what if, for example, you need to connect a laptop to an analog monitor or another device that has a DVI connector to a digital panel with HDMI or DisplayPort standard? Special adapters will help with this, which can be purchased today at any radio electronics store.

Let's look at their main types:

• VGA - DVI;
• DVI - VGA;
• DVI - HDMI;
• HDMI - DVI;
• HDMI - DisplayPort;
• DisplayPort - HDMI.

In addition to these basic adapters, there are also varieties of them that provide connection to other interfaces, such as USB.

Of course, with such a connection there is a loss of image quality, even between devices of the same type that support the DVI standard. An adapter connector, no matter how high-quality it is, cannot solve this problem.

How to connect a TV to a computer

Connecting a TV to a computer or laptop is not difficult, but you should determine which interface is equipped with both devices. Most modern television receivers have built-in connectors that support DVI. This can be either HDMI or DisplayPort. If a computer or laptop has the same connector as the TV, it is enough to use the cable that usually comes with the latter. If the wire was not included in the kit, you can freely buy it in the store.

The computer operating system will independently detect the connection of the second screen and offer one of the options for using it:

• as the main monitor;
• in clone mode (the image will be displayed on both screens);
• as an additional monitor to the main one.

But do not forget that with such a connection, the image resolution will remain the same as provided for by the screen design.

Does cable length affect signal quality?

Not only the signal quality, but also the data transfer speed depends on the length of the cable connecting the device and the screen. Taking into account the modern characteristics of connecting wires for various digital interfaces, their length should not exceed the established parameters:

• for VGA - no more than 3 m;
• for HDMI - no more than 5 m;
• for DVI - no more than 10 m;
• for DisplayPort - no more than 10 m.

If you need to connect a computer or laptop to a screen located at a distance exceeding the recommended one, you must use a special amplifier - a repeater (signal repeater), which can also distribute the channel to several monitors.

To transmit video signals in 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 transmitting an analog signal did not allow achieving high quality pictures, because it is physically impossible to transmit a high-resolution analog signal over a distance.

Video distortion can always occur in the communication channel, this is especially noticeable on high frequencies oh, and HD quality just 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 a digital interface for transmitting video data, eliminating 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 cable in the DVI cable, and a separate twisted pair cable to carry the clock 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 it is possible to 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. 1) DVI-D transmits only digital signal;
2. 2) DVI-A transmits only analog signal;
3. 3) DVI-I is used for transmission and digital signals and analog.

The connector itself for all three types is used the same, 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.

Same as HDMI interface DVI supports HDCP content protection system. Such a protection system is called intelligent protection and it is called so 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.