Dual channel dvi cable. Difference between DVI-I and DVI-D

To ensure video signal transmission to digital format, DVI is enabled. The interface was developed during the period when they began to release DVDs. At that time, there was a need to transfer video from a PC to a monitor.

The methods of transmitting analogue broadcasting known at that time were not conducive to transmitting high-quality images to the monitor. Since it is physically impossible to physically carry out such a high-resolution transmission at a distance.

Distortion can form in the channel at any moment, this can be especially observed on higher frequencies. HD is the owner high frequencies. To avoid this kind of interference and distortion, manufacturers modern technology set the goal of abandoning the analogue broadcast option and switching to a digital signal type in the process of processing and transmitting video to the monitor.

In the 90s, manufacturers joined forces, as a result of which DVI technology appeared.

The DVI connector is considered one of the most popular methods for connecting monitors and projects. The presence of a DVI interface on a device does not guarantee that the user will be able to realize all the capabilities available in this port. In this article we will look at DVI I and DVI D, the differences and similarities between these ports.

DVI Connector Features

Ports are responsible for transmitting images to the monitor. There are several modifications of the connector in question. Both digital and analog signals are transmitted. This type of port is most often represented by two options: DVI-I and DVI-D.

Is there a difference between them? DVI-D or DVI-I, which is better? More on this later.

DVI-I interface

This interface is considered the most used in video cards. “I” speaks of unification from the translation “integrated”. The port uses 2 channels for data transmission - analog and digital. Functioning separately, they have various modifications of DVI-I:

• Single Link. This device includes independent digital and analogue channels. The type of connection on the video adapter and how the connection occurs determines which one will function.

This type of interface is not used by professionals because it does not transmit to 30″ and LCD monitors.

• Dual Link– this is a modernized port, which contains: 2 digital and 1 analog channel. The channels operate independently of each other.

The difference is that most video cards have at least 2 DVI-I connectors.

DVI-D interface

This port looks different from the first DVI-I. The interface can accept a couple of channels. The first Single Link type contains only 1 channel, and it is not enough to connect to 3D monitors.

Dual Link is the second type. There are no analog channels, but the interface has wide options for transmitting information. Dual - indicates two channels, which makes it possible to send images to the monitor in three-dimensional format, since 2 channels have 120 Hz and are capable of transmitting high resolution.

The main differences between DVI-I and DVI-D

Majority modern models video cards are produced with a DVI interface instead of the classic, but outdated VGA. Of course, you shouldn't forget about HDMI. From what was said earlier, it is clear that DVI is available in two types. What's the difference between DVI-I and DVI-D?

The differences boil down to the following: I can transmit both analog and digital signal, and D is digital only. Thus, DVI-D is not suitable for connecting an analog monitor.

DVI is a digital video connector that replaced VGA. DVI-I is responsible for transmitting digital and analog signal. As for the analog signal, it is required for compatibility of older monitors with the beam tube. Time passed, and this option was no longer required; video cards began to use exclusively digital signals. As a result, DVI-D took over these tasks.

You need to understand that inserting a DVI-I adapter or the same type of cable into DVI-D will not work. Because the connector connectors are different. The DVI-D interface can be connected to “i” without any problems. This option allows you to receive an exclusively digital signal. Analog signals are not read in this situation, since the DVI-D connector does not have an “i” pin, which is responsible for transmitting an analog signal.

What do they have in common?

The differences between DVI-I and DVI-D have been examined, and we can begin to consider their combined characteristics.

DVI-I is universal and has the option of transmitting two types of signals: digital and analog. Due to the use of special additional elements in the form of adapters, and connection with other devices, “I” is able to transmit high-quality different formats. The use of this type for an analog signal has practically no bright distinctive features from "D".

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 image in digital form the output from it had to be converted into an analog signal using a RAMDAC device - a digital-to-analog converter. Naturally, such conversion is already initial stage deteriorated image quality.

With the advent digital screens there was a need 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 signal transmission through the digital video interface is based on the sequential sending of information pre-implemented by the protocol, with constant backward compatibility with the 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 s maximum frequency 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 by everyone without exception. digital devices Oh.

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. Video card connectors with digital interface impossible to confuse 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 the 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 our daily life, the following types of DVI connectors are most often found:

• 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, has two digital channel. 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 an 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 a digital channel and 5 for an analogue one;
• 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 “ multimedia interface with high resolution." 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 of 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. With high throughput, minimal loss quality in data transmission and compactness, it was designed to completely replace the DVI standard. But it turned out that not everything is so simple. Majority modern monitors do not have the appropriate connectors, and changing their production system in a short time is an impossible task. 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 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 its use:

• 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. Considering modern characteristics 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.

Often the choice of a video card is made according to the criteria of an already purchased monitor or its desired type and image quality. For example, a digital LCD monitor requires DVI connectors. Although modern developments often offer absolutely universal solutions, it’s still worth double-checking. Because for resolutions higher than 1920 by 1200 with digital image transmission, you only need a DVI Dual Link connector.

What are DVI connectors used for?

DVI connectors perform important functions transferring images to various types monitors, they are divided into several types, advanced digital and analog signals. Most modern video cards are equipped with a DVI interface, which is presented mainly in two different DVI-I types and DVI-D.

What is DVI-I?

This type is considered the most common in video cards due to its versatility. "I" stands for "integrated". This interface uses two types of transmission channel, namely analog and digital. They function separately from each other, and have different modifications:

This device has 1 digital channel and 1 analogue. They absolutely do not depend on each other. Which of them will function depends on the type of connection to the video card and on the mechanism directly to which the connection is made. This type is not used in professional equipment, because eliminates the possibility of transmission to thirty-inch and LCD monitors, namely the use of wider screen resolutions (more than 1920 by 1080).

What is DVI-D?

This interface provides exclusively digital technologies for data transmission, and can also have several channels. This type, namely DVI-D Single Link, allows feeding at a frequency 60 Hz, in resolution 1920 by 1200 dots, but this is not enough to connect to 3D monitors. In turn, there is a second type for this. Let's take a closer look at it!

D - this is “digital”, translated as “digital”, as mentioned above, it does not have an analog channel, but at the same time allows greater possibilities for transmitting digital data. Dual – means “2” channels. This advantage makes it possible to operate NVidia 3D, feeding images to a 3D monitor, because two channels allow 120 Hz and wide resolution capabilities.

Key differences between DVI-I and DVI-D

“I” supports both digital and analogue transmission forms; in “D” only digital is possible, so if connected to an analog monitor, DVI-D will not be able to transmit the right signal. Externally, they also differ; unlike dvi-i, dvi-d does not have four holes. The “D” connector is much less common on video cards, but it guarantees the most best quality digital image. Often used for professional CRT monitors. Mostly this type found in integrated video cards. When, in turn, it is dvi-i that is most common on popular consumer video cards, due to its two functionality. Considering the connection data, there is also exclusively analog form transmission is DVI-A, used very rarely.

What do they have in common?

Of course, this is the versatility of DVI-I and the ability to transmit, both digital and analog signal. With the help of additional adapters and combinations, “I” efficiently carries out any form of transmission, and the use of this type for an analog screen is almost no different from “D”. In modern products, the first option is used much more often than the second and, moreover, almost always!

If you have any doubts about the alignment of the video card and screen connectors, it is recommended to immediately contact a specialist, because Most often, in case of an error, you will have to either replace one of the devices or use possible alternatives and additional cables, which may distort the image. The best option It is considered to be purchasing DVI-D for a digital monitor, or a universal dvi-i that can function even when replacing an analog monitor with a digital one. For more information about which of the above connectors will provide the best quality, it is best to consult when purchasing.

A few years ago, VGA output was the main interface used to connect CRT (electro-ray tube) monitors and LCD (liquid crystal display) monitors.

VGA (Video Graphics Adapter) used to output an analog signal, the connector for which is respectively called VGA or D-Sub 15 (15-pin connector). You can also find the following decoding of the abbreviation VGA - Video Graphics Array (pixel array). The connector itself has 15 legs and most often blue. Subsequently, the digital interface DVI (Digital Visual Interface) began to be used for LCD monitors. But this output has not lost its popularity; it is still used in digital projectors, in some HDTVs and in game consoles from Microsoft.

HDMI

HDMI ( High Definition Multimedia Interface)— a multimedia interface that allows you to transmit audio over a cable up to 10 m along with a video signal without loss of quality. Transmitting video and audio data simultaneously over one cable reduces the number of connecting wires.
This standard is developed and supported by renowned companies in the electronics industry, such as Hitachi, Panasonic, Philips, Sony, Thomson and Toshiba. Thanks to this, the standard quickly gained popularity, and now most video devices for displaying images high resolution, has at least one HDMI connector.

In the first version of this standard throughput was 5 Gb/s, and in version 1.3 it was doubled and HDMI cable capable of transmitting up to 10.2 Gb/s. In addition, in HDMI versions 1.3, the synchronization frequency was increased to 340 MHz and thanks to this it became possible to connect high-resolution monitors with support for color depth up to 48 bits.

HDMI's main competitor is the DisplayPort connector.

If your video card does not have it, then this problem can be easily solved using an adapter and a DVI connector.

DVI output

DVI (Digital Visual Interface)– a digital interface that is used to connect a video card to LCD monitors, TVs, projectors, and plasma panels. DVI provides undistorted image output due to the fact that the video signal does not undergo double anlag/digital conversion, that is, the signal is transmitted directly. This is noticeable at high resolutions.

There are several types of DVI interface:
DVI-D— interface for outputting only a digital signal;
DVI-I– combined, which has analog lines (VGA). TO DVI-I monitors that have an analog connector are connected to the output via a special adapter.

Single-Link DVI and Dual-Link DVI

For signal transmission, single-channel Single-Link DVI or two-channel Dual-Link DVI are used.
Dual-Link DVI– an interface that allows you to display high-resolution images, more than 1920 x 1200 (such as 2560×1600 and 2048×1536), therefore, for LCD monitors with high resolution (for example, 30”), you need to select a video card that supports dual-channel DVI Dual-Link output.

S-Video (or S-VHS)

S-Video (or S-VHS)- an analog connector that is used to output images to televisions and video equipment. So far, the quality of signal transmission is superior to the “tulip” type output. The analogue S-Video interface provides a low-resolution signal where all information is divided into three channels for each base color. Although the quality is better, we still have low dynamic resolution.

Composite RCA output (tulip)

Composite output or connector RCA (Radio Corporation of America).
A common output found on televisions and video equipment. Used for connection coaxial cable. The output produces a low-resolution signal and the video quality is correspondingly low.

Component output

Because of large size component connectors, the outputs are located on the adapter. The first three connectors are responsible for video, the last two for audio.
It consists of three separate “tulip” connectors: “Y”, “Pb” and “Pr”. This results in a split color output for HDTV. Used to display images on digital projectors.

Interfaces currently in widespread use:

VGA

DVI-D

DVI-I

HDMI

Legacy and exotic interfaces: