Dvi digital or analog. We determine the DVI type by the appearance of the connector on the video card


Interfaces currently in widespread use:

VGA

(D-Sub)- the only one analog interface connection of monitors, still used today. Morally outdated, but will be actively used again long time. The main disadvantage is associated with the need to use double conversion of the signal to analog format and vice versa, which leads to loss of quality when connecting digital devices display (LCD monitors, plasma panels, projectors). Compatible with video cards with DVI-I and similar connectors.

DVI-D

- basic type DVI interface. Implies only digital connection, therefore cannot be used with video cards that only have an analog output. Very widespread.

DVI-I

- an extended version of the DVI-D interface, the most commonly used nowadays. Contains 2 types of signals - digital and analog. Video cards can be connected via both digital and analog connections; a video card with a VGA (D-Sub) output can be connected to it via a simple passive adapter or a special cable.
If the documentation for the monitor indicates that this modification uses the DVI Dual-Link option, then in order to fully support the maximum monitor resolutions (usually 1920*1200 and higher), the video card and the DVI cable used must also support Dual-Link as a full interface option DVD-D. If you use the cable included with the monitor and a relatively modern (at the time of writing the FAQ) video card, then no additional purchases are required.

HDMI

- adaptation of DVI-D for household equipment, supplemented by a digital interface for multi-channel audio transmission. Present in virtually all modern LCD TVs, plasma panels and projectors. To connect a video card with a DVI-D or DVI-I interface to the HDMI connector, a simple passive adapter or cable with appropriate connectors is sufficient. It is impossible to connect a video card with only a VGA (D-Sub) connector to HDMI!

Legacy and exotic interfaces:

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 transmission analog signal were not allowed to achieve High Quality pictures, because physically transmit an analog signal high resolution at a distance is impossible.

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 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 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 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 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 carry signal from high resolution and on long 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 contains 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 called so because of its implementation and the ability to set different levels of protection depending on the different cases, so this 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 via 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.

The choice of video card can also be influenced by the monitor you have or are planning to purchase. Or even monitors (plural). So, for modern LCD monitors with digital inputs, it is very desirable that the video card have a DVI, HDMI or DisplayPort connector. Fortunately, for everyone modern solutions Now there are such ports, and often all together. Another subtlety is that if you require a resolution higher than 1920x1200 via the digital DVI output, then you must connect the video card to the monitor using a connector and cable that supports Dual-Link DVI. However, now there are no problems with this anymore. Let's look at the main connectors used to connect information display devices.

Analog D-Sub connector (also known as VGA-exit or DB-15F)

This is a long-known and familiar 15-pin connector for connecting analog monitors. The abbreviation VGA stands for video graphics array (pixel array) or video graphics adapter (video adapter). The connector is designed to output an analog signal, the quality of which can be influenced by many different factors, such as the quality of RAMDAC and analog circuits, so the quality of the resulting image may vary on different video cards. Besides, in modern video cards ah quality analog output less attention is paid, and to get clear pictures at high resolutions it is better to use a digital connection.

D-Sub connectors were actually the only standard until the widespread use of LCD monitors. Such outputs are still often used to connect LCD monitors, but only budget models, which are not suitable for games. To connect modern monitors and projectors, it is recommended to use digital interfaces, one of the most common of which is DVI.

Connector DVI(variations: DVI-I And DVI-D)

DVI is the standard interface most often used to output digital video to all but the cheapest LCD monitors. The photo shows quite old video card with three connectors: D-Sub, S-Video and DVI. There are three types of DVI connectors: DVI-D (digital), DVI-A (analog) and DVI-I (integrated - combined or universal):

DVI-D- an exclusively digital connection, which avoids losses in quality due to double conversion of the digital signal to analog and from analog to digital. This type of connection provides the highest quality picture, it outputs the signal only in digital form, digital LCD monitors with DVI inputs or professional CRT monitors with built-in RAMDAC and a DVI input can be connected to it (very rare copies, especially now). This connector differs from DVI-I in the physical absence of some contacts, and the DVI-to-D-Sub adapter, which will be discussed later, cannot be plugged into it. Most often this type of DVI is used in motherboards with an integrated video core, it is less common on video cards.

DVI-A- This is a rather rare type of analog connection via DVI, designed to output analog images to CRT receivers. In this case, the signal is degraded due to dual digital-to-analog and analog-to-digital conversion, its quality is equal to that of a standard VGA connection. Almost never found in nature.

DVI-I is a combination of the two options described above, capable of transmitting both analog and digital signals. This type is used most often in video cards; it is universal and, using special adapters that come with most video cards, you can also connect a regular analog CRT monitor with a DB-15F input to it. This is what these adapters look like:

All modern video cards have at least one DVI output, or even two universal ones. DVI-I connector. D-Subs are most often absent (but they can be connected using adapters, see above), except, again, for budget models. To transmit digital data, either a single-channel DVI Single-Link solution or a two-channel Dual-Link solution is used. Single-Link transmission format uses one TMDS transmitter (165 MHz) and Dual-Link two, it doubles the bandwidth and allows screen resolutions higher than 1920x1080 and 1920x1200 at 60Hz, supporting very high resolution modes , like 2560x1600. Therefore, for the largest LCD monitors with high resolution, such as 30-inch models, as well as monitors designed to display stereo images, you will definitely need a video card with a dual-channel DVI Dual-Link or HDMI version 1.3 output.

Connector HDMI

IN Lately a new one has become widespread home interface — High Definition Multimedia Interface. This 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 the HDMI connector.

In the photo on the left is HDMI, on the right is DVI-I. HDMI outputs on video cards are now quite common, and there are more and more such models, especially in the case of video cards intended for creating media centers. Viewing high-definition video on a computer requires a video card and monitor that support HDCP content protection, connected by an HDMI or DVI cable. Video cards do not necessarily have to have an HDMI connector on board; in other cases, the HDMI cable can also be connected via an adapter to DVI:

HDMI is another attempt at standardization universal connection for digital audio and video applications. It immediately received strong support from the giants of the electronics industry (the group of companies involved in developing the standard includes companies such as Sony, Toshiba, Hitachi, Panasonic, Thomson, Philips and Silicon Image), and most modern high-resolution output devices have although There would be one such connector. HDMI allows you to transmit copy-protected audio and video in digital format over a single cable; the first version of the standard was based on a bandwidth of 5 Gbps, and HDMI 1.3 expanded this limit to 10.2 Gbps.

HDMI 1.3 is an updated standard specification with increased interface bandwidth, increased clock frequency to 340 MHz, which allows you to connect high-resolution displays that support more colors (formats with color depths up to 48 bits). 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 mini-HDMI connector, smaller in size compared to the original. Such connectors are also used on video cards.

HDMI 1.4b is the latest new version of this standard, which came out not so long ago. HDMI 1.4 introduced the following major innovations: support for stereo display format (also called "3D") with frame-by-frame transmission and active viewing glasses, support for Fast Ethernet connection HDMI Ethernet Channel for data transmission, audio return channel, which allows digital audio to be transmitted in the reverse direction , support for resolution formats 3840x2160 up to 30 Hz and 4096x2160 up to 24 Hz, support for new color spaces and the smallest micro-HDMI connector.

In HDMI 1.4a, stereo display support has been significantly improved, with new Side-by-Side and Top-and-Bottom modes in addition to the 1.4 specification modes. And finally, a very recent update to the HDMI 1.4b standard occurred just a few weeks ago, and the innovations of this version are still unknown to the general public, and there are no devices with its support on the market yet.

Actually, the presence HDMI connector on a video card is not necessary; in many cases it can be replaced by an adapter from DVI to HDMI. It is simple and therefore included with most modern video cards. Moreover, modern GPUs have a built-in audio chip necessary to support audio transmission over HDMI. On all modern AMD video cards and NVIDIA there is no need for an external audio solution and associated connecting cables, and there is no need to transmit audio from an external sound card.

Transmission of video and audio signals via one HDMI connector is in demand primarily on mid-range and lower levels, which are installed in small and quiet barebones used as media centers, although HDMI is often used in gaming solutions, largely due to the spread household appliances with these connectors.

Connector

Gradually, in addition to the common video interfaces DVI and HDMI, solutions with the DisplayPort interface are appearing on the market. Single-Link DVI transmits a video signal with a resolution of up to 1920x1080 pixels, a frequency of 60 Hz and 8 bits per color component, Dual-Link allows transmission of 2560x1600 at a frequency of 60 Hz, but already 3840x2400 pixels under the same conditions for Dual-Link Link DVI not available. HDMI has almost the same limitations; version 1.3 supports signal transmission with a resolution of up to 2560x1600 pixels at a frequency of 60 Hz and 8 bits per color component (at lower resolutions - 16 bits). Although maximum possibilities DisplayPort is slightly higher than Dual-Link DVI, with only 2560x2048 pixels at 60Hz and 8 bits per color channel, but it does have support for 10-bit color per channel at 2560x1600 resolution, as well as 12 bits for the format 1080p.

The first version of the DisplayPort digital video interface was adopted by VESA (Video Electronics Standards Association) in the spring of 2006. It defines a new universal digital interface, license-free and royalty-free, designed to connect computers and monitors, as well as other multimedia equipment. The VESA DisplayPort group promoting the standard includes large manufacturers electronics: AMD, NVIDIA, Dell, HP, Intel, Lenovo, Molex, Philips, Samsung.

DisplayPort's main competitor is the HDMI connector, which supports HDCP write protection, although it is intended more for connecting consumer digital devices such as players and HDTV panels. Another competitor could previously be called Unified Display Interface - less expensive alternative HDMI connectors and DVI, but its main developer, Intel, refused to promote the standard in favor of DisplayPort.

The absence of licensing fees is important for manufacturers, because in order to use the HDMI interface in their products, they are required to pay license fees to HDMI Licensing, which then divides the funds between the holders of rights to the standard: Panasonic, Philips, Hitachi, Silicon Image, Sony, Thomson and Toshiba. Abandoning HDMI in favor of a similar “free” universal interface will save manufacturers of video cards and monitors a lot of money - it’s clear why they liked DisplayPort.

Technically, the DisplayPort connector supports up to four data lines, each of which can transmit 1.3, 2.2 or 4.3 gigabits/s, for a total of up to 17.28 gigabits/s. Modes with color depth from 6 to 16 bits per color channel are supported. An additional bidirectional channel, designed to transmit commands and control information, operates at a speed of 1 megabit/s or 720 megabit/s and is used to service the operation of the main channel, as well as the transmission of VESA EDID and VESA MCCS signals. Also, unlike DVI, the clock signal is transmitted along signal lines, rather than separately, and is decoded by the receiver.

DisplayPort has optional DPCP (DisplayPort Content Protection) copy protection capability developed by AMD and using 128-bit AES encoding. The transmitted video signal is not compatible with DVI and HDMI, but according to the specification their transmission is allowed. On this moment DisplayPort supports a maximum data transfer rate of 17.28 gigabits/s and a resolution of 3840x2160 at 60 Hz.

Basic distinctive features DisplayPort: an open and extensible standard; support RGB formats and YCbCr; color depth support: 6, 8, 10, 12 and 16 bits per color component; broadcast full signal at 3 meters, and 1080p at 15 meters; support for 128-bit AES encoding DisplayPort Content Protection, as well as 40-bit High-bandwidth Digital Content Protection (HDCP 1.3); greater bandwidth compared to Dual-Link DVI and HDMI; transmission of multiple streams over one connection; compatibility with DVI, HDMI and VGA using adapters; simple expansion of the standard to meet changing market needs; external and internal connections (connecting an LCD panel in a laptop, replacing internal LVDS connections).

The updated version of the standard, 1.1, appeared a year after 1.0. Its innovations include support for HDCP copy protection, important when viewing protected content from Blu-ray discs and HD DVDs, and support for fiber optic cables in addition to conventional copper cables. The latter allows you to transmit a signal over even greater distances without loss of quality.

DisplayPort 1.2, approved in 2009, doubled the interface's throughput to 17.28 gigabits/s, allowing it to support higher resolutions, screen refresh rates, and color depths. Also, it was in 1.2 that support for transmitting multiple streams over one connection for connecting multiple monitors, support for stereo display formats and xvYCC, scRGB and Adobe RGB color spaces appeared. A smaller Mini-DisplayPort connector for portable devices has also appeared.

The full-size external DisplayPort connector has 20 pins, its physical size can be compared to all known USB connectors. A new type of connector can already be seen on many modern video cards and monitors; it looks similar to both HDMI and USB, but can also be equipped with latches on the connectors, similar to those provided in Serial ATA.

Before AMD bought ATI, the latter announced the supply of video cards with DisplayPort connectors at the beginning of 2007, but the merger of companies delayed this appearance for some time. AMD subsequently announced DisplayPort standard connector as part of the Fusion platform, which implies a unified architecture of central and graphic processors in one chip, as well as future mobile platforms. NVIDIA is keeping up with its rivals by releasing a wide range of DisplayPort-enabled graphics cards.

Among the monitor manufacturers that announced support and announced DisplayPort products, Samsung and Dell were the first. Naturally, such support was first received by new monitors with a large screen diagonal size and high resolution. There are DisplayPort-to-HDMI and DisplayPort-to-DVI adapters, as well as DisplayPort-to-VGA, which converts a digital signal to analog. That is, even if the video card contains only DisplayPort connectors, they can be connected to any type of monitor.

In addition to the connectors listed above, older video cards also sometimes have a composite connector and S-Video (S-VHS) with four or seven pins. Most often they are used to output a signal to outdated analog television receivers, and even on S-Video the composite signal is often mixed, which negatively affects the picture quality. S-Video is better quality than composite tulip, but both are inferior to YPbPr component output. This connector is found on some monitors and high-definition TVs; the signal is transmitted through it in analog form and is comparable in quality to the D-Sub interface. However, in the case of modern video cards and monitors, paying attention to all analog connectors simply does not make any sense.

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 high-resolution output has at least one such connector. HDMI allows you to transmit copy-protected audio and video in digital format over a single cable; the first version of the standard was based on a bandwidth of 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). The new version of the specification also defines support for new Dolby standards for transmitting compressed audio without loss in 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

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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.
  • Used high speed technology TMDS: three channels processing video streams at speeds up to 3.4 Gbps per channel.
  • 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 pair: 3 of them transmit RGB signals (green, red, blue) and the 4th one is for 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 insufficient. 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.

Difference between DVI and HDMI

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 signal, and the second - exclusively with numbers.
  • The modern interface comes with built-in Ethernet channel with a speed of 100 Mbit, and DVI does not offer such a bonus.

Both connectors produce the same image quality.

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 channel.
  • DVI-D 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 3D Vision technology.

- Dual Link assumes 2 digital channel, 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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