What does the dvi connector look like? Interfaces

Interfaces currently in widespread use:

VGA

DVI-D

DVI-I

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 transmitting an analog signal did not allow achieving high picture quality, because it was 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 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 these are 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 allowed 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 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 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 is called so because of its implementation and the ability to set different levels of 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.

The DVI connector is used in modern televisions (plasma, liquid crystal), LCD monitors and video cards of personal computers. The name "DVI" comes from the English abbreviation Digital VisualInterface, which translates as "digital video interface". The DVI connector was developed and first introduced back in 1999 by the Digital Display Working Group. It includes global giants in the production of computer equipment and monitors, such as Intel, Compaq, Fujitsu, Silicon Image, Hewlett Packard and NEC. The DVI connector replaced the VGA interface and today has almost completely replaced it.

Description of DVI technology

The method used in this interface was developed by Silicon Image. It is a type of serial communication device. The DVI cable is built on the twisted pair principle. Three pairs of wires carry colors (red, green and blue), and the fourth carries clock signals. The DVI connector allows you to transmit both analog and There are three subtypes of the interface in question:

• DVI-A - used for transmission exclusively;
• DVI-I is a universal connector, used for transmitting both analog and digital signals;
• DVI-D - for transmitting digital signals only.

In addition, DVI technology is equipped with a special HDCP digital information protection system developed by Intel.

Disadvantages of the DVI interface

The main disadvantage of transmitting information through this connector is the limitation of the cable length, as well as the dependence of the mentioned parameter on the type of signal being transmitted. For example, an image with an extension of 1920x1200 pixels at a frequency of 60 Hz can be transmitted over a cable whose length is 5 meters, and through a fifteen-meter cable it is possible to transmit a signal whose maximum quality is only 1280x1024 pixels at the same frequency. Therefore, if it is necessary to use long cables, it is necessary to use additional equipment - special signal amplifiers (repeaters), which are installed at certain distances. This disadvantage is associated with the appearance of dots on the monitor when using a low-quality cable. To eliminate this effect, you must either change the cord or reduce the quality of the input signal.

DVI-HDMI connector

This digital connector is used to transmit HDTV signals. Designed to connect TVs to various signal sources. A special feature of this connector is that it can transmit not only a video signal, but also digital audio. It allows you to broadcast 8 audio channels with a bit depth of 24 bits. There are various specifications for the designated interface, as well as adapters, thanks to which you can connect different types of connectors. The HDMI connector can also be used to connect a personal computer and a TV. It should be remembered that the HDMI-DVI interface supports a special protocol designed to protect licensed content from unauthorized overwriting.

Conclusion

Despite the fact that DVI technology has almost completely replaced VGA interfaces, today this type is quite widely used on older PCs. If your video card does not have a DVI connector, but you still need to connect a monitor that supports this technology, then you can use a special adapter - a DVI-VGA connector.

Hello, dear readers! Today I would like to talk about ways to connect a monitor to a video card - about video card connectors. Modern video cards have not one, but several ports for connection, so that it is possible to connect more than one monitor at the same time. Among these ports there are both outdated and now rarely used, and modern ones.

The abbreviation VGA stands for video graphics array (an array of pixels) or video graphics adapter (video adapter). Appeared back in 1987, 15-pin and, as a rule, blue, designed to output a strictly analog signal, the quality of which, as is known, can be affected by many different factors (wire length, for example), including on the video card itself, Therefore, the picture quality through this port on different video cards may vary slightly.

Before the widespread use of LCD monitors, this connector was almost the only possible option for connecting a monitor to a computer. It is still used today, but only in budget models of low-resolution monitors, as well as in projectors and some game consoles, such as the latest generation xbox consoles from Microsoft. It is not recommended to connect a Full HD monitor through it, as the picture will be blurry and unclear. The maximum VGA cable length at 1600 x 1200 resolution is 5 meters.

DVI (variations: DVI-I, DVI-A and DVI-D)

Used to transmit a digital signal, replacing VGA. Used to connect high-resolution monitors, televisions, as well as modern digital projectors and plasma panels. The maximum cable length is 10 meters.

The higher the resolution of the image, the shorter the distance it can be transmitted without loss of quality (without the use of special equipment).

There are three types of DVI ports: DVI-D (digital), DVI-A (analog) and DVI-I (combo):

To transmit digital data, either Single-Link or Dual-Link format is used. Single-Link DVI uses a single TMDS transmitter, while Dual-Link doubles the bandwidth and allows screen resolutions higher than 1920 x 1200, such as 2560 x 1600. Therefore, for large monitors with high resolution, or intended for stereo image output, you definitely need at least DVI Dual-Link, or HDMI version 1.3 (more on this below).

HDMI

Also digital output. Its main difference from DVI is that HDMI, in addition to transmitting a video signal, is capable of transmitting a multi-channel digital audio signal. Audio and visual information are transmitted over one cable at the same time. Initially developed for television and cinema, and later gained wide popularity among PC users. It is backward compatible with DVI using a special adapter. The maximum length of a regular HDMI cable is up to 5 meters.

HDMI is another attempt to standardize universal connectivity for digital audio and video applications, so it immediately received strong support from electronics giants (companies such as Sony, Hitachi, Panasonic, Toshiba, Thomson, Philips) contributed to the development, and as a result, most modern devices for outputting high-resolution images have at least one HDMI output.

Among other things, HDMI, like DVI, allows you to transmit copy-pasted sound and image in digital form over one cable using HDCP. True, to implement this technology you will need a video card and a monitor, attention! - supporting this technology, oh how. Again, there are currently several versions of HDMI, here's a short summary of them:

DisplayPort

Appeared in addition to DVI and HDMI, since Single-Link DVI can transmit a signal with a resolution of up to 1920x1080, and Dual-Link a maximum of 2560x1600, then a resolution of 3840x2400 is not available for DVI. The maximum resolution capabilities of DisplayPort are no different from the same HDMI - 3840 x 2160, however, it still has unobvious advantages. One of these is, for example, that companies will not have to pay tax for using DisplayPort in their devices - which, by the way, is mandatory when it comes to HDMI.

In the photo, red arrows indicate latches that prevent the connector from accidentally falling out of the connector. Even version 2.0 of HDMI does not provide any clamps.

As you already understood, DisplayPort's main competitor is HDMI. DisplayPort has an alternative technology to protect transmitted data from theft, only it is called a little differently - DPCP (DisplayPort Content Protection). DisplayPort, like HDMI, supports 3D images and audio content transmission. However, audio transmission via DisplayPort is only available one-way. And transmitting Ethernet data via DisplayPort is generally impossible.

DisplayPort also benefits from the fact that it has adapters for all popular outputs, such as DVI, HDMI, VGA (which is important). For example, with HDMI there is only one adapter - to DVI. That is, having only one DisplayPort connector on the video card, you can connect an old monitor with only one VGA input.

By the way, this is what is happening - now more and more video cards are being released without a VGA output at all. The maximum length of a regular DisplayPort cable can be up to 15 meters. But DisplayPort can transmit its maximum resolution at a distance of no more than 3 meters - often this is enough to connect the monitor and video card.

S-Video (TV/OUT)

On older video cards, you sometimes find an S-Video connector, or, as it is also called, S-VHS. It is usually used to output an analog signal to outdated TVs, however, in terms of the quality of the transmitted image it is inferior to the more common VGA. When using a high-quality cable via S-Video, the image is transmitted without interference at a distance of up to 20 meters. Currently extremely rare (on video cards).

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, all modern solutions now have 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. In addition, in modern video cards less attention is paid to the quality of the analog output, and to obtain clear images 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 that are not well suited for gaming. 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 a rather 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 DVI-I connectors. 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 output stereo images, you will definitely need a video card with a dual-channel DVI Dual-Link or HDMI version 1.3 output.

Connector HDMI

Recently, a new consumer interface has become widespread - 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 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 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). 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 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, released 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 of an HDMI connector on the 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 and NVIDIA video cards, there is no need for an external audio solution and corresponding connecting cables, and there is no need to transfer audio from an external sound card.

Transmission of video and audio signals via one HDMI connector is in demand primarily on mid- and low-end cards, which are installed in small and quiet barebones used as media centers, although HDMI is often used in gaming solutions, largely due to the proliferation of 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 DisplayPort's maximum capabilities are slightly higher than Dual-Link DVI's, only 2560x2048 pixels at 60 Hz and 8 bits per color channel, it does have support for 10-bit color per channel at 2560x1600 resolution, as well as 12 bit for 1080p format.

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 that promotes the standard includes large electronics manufacturers: 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 - a less expensive alternative to HDMI and DVI connectors, 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. Currently, DisplayPort supports a maximum data transfer rate of 17.28 gigabits/s and a resolution of 3840x2160 at 60 Hz.

The main distinctive features of DisplayPort: an open and extensible standard; support for RGB and YCbCr formats; color depth support: 6, 8, 10, 12 and 16 bits per color component; full signal transmission 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 pushed back this appearance for some time. Subsequently, AMD announced DisplayPort as a standard connector within 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.