#VGA #DVI-D #DVI-I #HDMI #DisplayPort

Interfaces that are widely used at the present time:

VGA

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

DVI-D

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

DVI-I

- an extended version of the DVI-D interface, the most common at the present time. 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 through 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 that came 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 consumer equipment, supplemented by a digital interface for transmitting multi-channel audio. It is present in virtually all modern LCD TVs, plasma panels and projectors. To connect to the HDMI connector of a video card with a DVI-D or DVI-I interface, a simple passive adapter or cable with the appropriate connectors is enough. It is impossible to connect a video card with only a VGA (D-Sub) connector to HDMI!

Legacy and exotic interfaces:

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 changed, the brightness also changed, which for LCD monitor is not recommended. In addition, it has already begun to approach the threshold of bandwidth required for large resolutions. Yes, and an extra signal converter at the monitor input, definitely did not improve the picture. Later, the problem of changing the brightness for D-Sub decided, and the interface is still used in budget monitors in a single instance, or for compatibility in conjunction with digital inputs.

Serial format is used for data transmission Panel Link which uses T range M imimized D differentialS ignaling (signal transmission with minimal signal changes). Supported 3 streams to transfer data at speeds up to before3.96 Gbps.

For achievement top speed transmission, it is necessary that the cable length does not exceed 1.5 meters. With increasing length, signal starts fade out, so when connecting over long distances, you need to use special active amplifiers. Also, the ability to transmit a signal is highly dependent on wire quality, their resistances, etc.

Designations and types of DVI connectors:

• DVI-D- support for digital transmission only

• DVI-A - support for analog transmission only

• DVI-I - support for analog and digital transmission

connector transmits 24 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 dual channel ( dual-link) mode, the maximum resolution is - 3,840 × 2,400 X 33 Hz or 2,560 × 1,600 at standard 60 Hz.

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

• · Squeezing, twisting of the cable.

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

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

• · The resolution is too high and hence the lack of bandwidth.

Before 2015 year is planned to completely replace DVI new standard -

DVI (digital visual interface) connector is used for digital video signal transmission. It was created when digital video media appeared - DVD discs, and when it was necessary to transfer video from the computer to the monitor. The methods of transmission then existing analog signal did not allow to achieve high picture quality, because it is impossible to physically transmit a high-resolution analog signal over a distance.

Video distortion can always occur in the communication channel, this is especially noticeable at high frequencies, and HD quality just implies the presence of high frequencies in the signal spectrum. In order to avoid these distortions, they tried to switch to a digital signal and abandon the analog signal when processing and transmitting video from a carrier to a display device. That's when, at the end of the 90s, several companies joined forces to create a digital video data transmission interface, excluding DAC (digital-to-analog) and ADC (analog-to-digital) converters from the path. The result of their work was the creation of a video signal transmission format - DVI.

Appearance dvi connector:

View of the dvi connector inside:

Basic parameters of the dvi interface

In this type of connection, information is transmitted about the main components of the RGB signal (red, green, blue). Each component uses a separate twisted pair in the DVI cable, and a separate twisted pair for transmission of synchronization signals. It turns out that the DVI cable consists of four twisted pairs. A twisted-pair connection allows using the principle of differential data transmission, when the interference has a different phase in each conductor and is subtracted in the receiver, but this technical features and you don't need to know them. 8 bits are assigned to each color component, and, in general, 24 bits of information are transmitted to each pixel. The maximum data transfer rate reaches 4.95 Gb / s, at this rate it is possible to transmit a signal with a resolution of 2.6 megapixels at a frame rate of 60 Hz. The HDTV signal, whose resolution is 1980x1080, has a resolution of just over 2 megapixels, so it turns out that a high-resolution signal of 1980x1080 at 60 Hz can be transmitted through the DVI connector. Only there is a limit on the length of the cable. 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, an increase in the length of the DVI cable is allowed. It is also possible to use intermediate amplifiers, if you still need a longer length for video signal transmission.

For greater compatibility, the DVI connector was made with the ability to support an analog signal. So there were three types of DVI connectors:

1. 1) DVI-D transmits only a digital signal;
2. 2) DVI-A only transmits analog signal;
3. 3) DVI-I is used to transmit both digital and analog signals.

The connector itself for all three types is used the same, so they are fully compatible, only they have a difference in the plug-in 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 means that DVI Dual Link cables can transmit higher resolution signals over long distances. That is, if when using a single link cable on the LCD TV image there will be interference 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 for the transmission of color components.

Features of dvi connector

To achieve these speeds, a special TMDS encoding method. And in any DVI connection, a TMDS transmitter is used for encoding on the transmitting side, and the RGB signal is restored on the receiving side.

Optionally can be used in DVI interface DDC (Display Data Channel) channel, which passes the EDID display information to the signal source processor. This information contains detailed information about the display device and includes brand, model number, serial number, release date, screen resolution, screen size information. Depending on this information, the source will output a signal with the desired resolution and screen proportions. In case of refusal to give out such information, the source may block the TMDS channel.

As well 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 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 password exchange by 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. In some video cards, it is possible to transmit sound over a dvi cable, but special adapters are used for this, and this possibility is additionally implemented in the video card itself. And then it is no longer a pure dvi interface. With a normal connection, the sound needs to be transmitted additionally.

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 another attempt to standardize universal connectivity for digital audio and video applications. It immediately received strong support from the giants of the electronics industry (the group of companies involved in the development of 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 transfer copy-protected sound and digital video over a single cable, the first version of the standard is 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 depth up to 48-bit). new version specifications are defined and support for the new Dolby standards for the transmission of lossless compressed audio in quality. In addition, other innovations appeared, in specification 1.3 a new connector was described, which is smaller in size compared to the original one.

In principle, the presence of an HDMI connector on a video card is completely optional; it is successfully replaced by an adapter from DVI to HDMI. It is simple and therefore is included in the kit of most modern video cards. Moreover, on video cards of the HDMI series, the connector is in demand primarily on cards of the middle and lower levels, 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 assemblers of such multimedia centers.

Based on materials from the company's website iXBT.com

We select the appropriate plug for the appropriate connector. What types of cables are offered by manufacturers "HDMI,DVI,VGA,DisplayPort" and which interface is optimal for connecting a monitor.

Previously, to connect a monitor to a computer, only an analog interface was used. VGA. Modern devices have connectors "HDMI, DVI, VGA, DisplayPort". Let's see what advantages and disadvantages each of the interfaces has.

With the development of new technologies for flat-panel monitors, the connector capabilities have become insufficient VGA. In order to achieve the highest image quality, it is necessary to use a digital standard such as DVI. Home entertainment device manufacturers have created a standard HDMI, which has become the digital successor” of the analog Scan connector. Somewhat later, VESA (Video Electronics Standards Association) developed display port.

The main interfaces for connecting monitors.

■ VGA. The first connection standard still in use today was developed in 1987 by then-leading computer manufacturer IBM for its PS/2 series PCs. VGA is the abbreviated Video Graphics Array (pixel array), at one time this was the name of the video card in PS / 2 computers, the resolution of which was 640x480 pix (the combination “VGA resolution” often found in technical literature means exactly this value).

An analog data transmission system with an increase in resolution only worsens the quality of the picture. Therefore, in modern computers, the digital interface is the standard.

. ■ DVI. This abbreviation oz-naHaeTDigital Visual Interface is a digital video interface. It transmits the video signal in digital format while maintaining high image quality.

DVI is backwards compatible: almost all computers are equipped with a DVI-I connector that can carry both digital video and VGA.

Inexpensive video cards are equipped with a DVI output in the Single Link modification (single-channel solution). Maximum resolution in this case is 1920x 1080 pix. (Full HD). More expensive models of video cards have a two-channel DVI (Dual Link) interface. They can be connected to monitors with resolutions up to 2560x1600 pix.

The DVI connector is large enough that Apple designed the Mini DVI interface for their laptops. Using the adapter, you can connect devices with Mini DVI and to monitors equipped with a DVI connector.

connection interfaces

■HDMI. The abbreviation HDMI stands for High Definition Multimedia Interface, that is, a high-definition multimedia interface. In modern home entertainment devices such as flat-panel TVs and Blu-ray players, HDMI is the standard connection interface.

As with DVI, the signal is transmitted digitally, which means that the original quality is preserved. Together with HDMI, HDCP (High Bandwidth Digital Content Protection) protection technology was developed, which prevents the creation of exact copies, for example, of video materials.

The first HDMI-enabled devices appeared in late 2003. Since then, the standard has undergone several changes, in particular, support for new audio and video formats has been added (see table above).

For miniature models of equipment, there is a Mini HDMI interface; An appropriate HDMI/Mini HMDI cable is included with many devices.

■ Display Port(DP). A new type of digital interface for connecting video cards with display devices is designed to replace DVI. The current version of the standard 1.2 allows you to connect multiple monitors when they are connected in series in one chain. However, at present, there are not so many devices that have a DP port. As a direct competitor to HDMI, given interface has a significant advantage from the point of view of manufacturers: it does not require license fees. While for each device with HDMI you have to pay four US cents. If the connector of a computer or laptop has the designation "DP ++", this indicates that using an adapter you can connect monitors with DVI and HDMI interfaces.

In order to leave enough space on the back of modern video cards for connectors for other purposes, a smaller version of the DP interface was developed. For example, Radeon HD6800 series graphics cards have up to six Mini DP ports.

HDMI,DVI,VGA,DisplayPort

Which of these standards will be the most widely adopted? HDMI has a very high chance of success, because most devices have this interface. However, there is a new trump card in the deck of Asian manufacturers: according to official data, the Digital Interactive Interface for Video and Audio (DiiVA) provides a bandwidth of 13.5 Gb / s (DP: 21.6; HDMI: 10.21. In addition, the companies promise that the maximum cable length between devices such as a Blu-ray player and a TV will be up to 25m. No word yet on what the DiiVA interface looks like.

USB video transfer

Two years ago, it became possible to connect monitors via USB using DisplayLink adapters. However, due to the low (480 Mbps) bandwidth, a USB 2.0 connection is unsuitable for video transmission. Another thing is the latest version of the USB standard (3.0), which provides data transfer rates up to 5 Gb / s.
The DisplayLink adapter allows you to connect monitors directly to your computer's USB port.

How to connect a computer and a monitor with different interfaces.

Thanks to the adapters, there are many connection options (see table below).

Common adapters, such as DVI-I / VGA, are quite affordable. So-called converters that convert the digital DisplayPort signal to an analog VGA signal are much more expensive.

However, for example, when you connect a TV with an HDMI interface to the DVI connector, there is almost always no sound.

Is it possible to combine devices with different versions HDMI

With this combination, only the functions of an earlier version of the corresponding interface will be available. For example, if a video card with HDMI 1.2 is connected to a 3D TV that supports HDMI 1.4, 3D games will only be displayed in 2D.
Advice. Installing the new driver allows you to add HDMI 1.4 support to some video cards based on NVIDIA chips, such as the GeForce GTX 460.
Which connectors provide the best picture quality?

As tests have shown, the analog VGA interface gives the worst image quality, especially when transmitting signals with a resolution of more than 1024x768 pix. Even 17-inch monitors support this resolution today. Owners of monitors with a larger diagonal and a resolution of 1920x1080 pix are strongly recommended to use DVI, HDMI or DP.

How to connect a monitor to a laptop?

Most laptops are equipped with connectors for connecting external monitors. Connect the monitor to the laptop first. After that, using the W and KPI buttons, you can switch between the following modes.

■ Using an external monitor as the main monitor. The laptop display turns off, the image is displayed only on the connected external monitor. The best option for movie buffs and gamers.

clone mode. External monitor and laptop display show the same image

■ Practical function for presentations and seminars.

■ Multi-screen mode. Allows you to increase the size of your Windows desktop by using multiple monitors. It is very convenient, for example, when typing text in Word, to have electronic messages in front of your eyes.

Can you connect a TV to a computer?

IN modern computers and laptops lack analog video interfaces such as S-Video or composite. Therefore, connecting an old CRT TV will definitely not work. However, the vast majority of flat models are equipped with DVI or HDMI interfaces, which means that connecting them to a computer is not difficult.

Netbooks, as a rule, have only a VGA output, and only those TVs that have a VGA input can be connected to them.

Is it possible to connect a monitor via USB

For traditional monitors, this is only possible with the optional DisplayLink adapter. However, there are also models on sale that connect directly to the computer's USB port - for example, Samsung SyncMaster 940 UX.

What is the maximum cable length for the monitor?

The capabilities of the cable depend on the type of connection. When using DVI, the connection length can be up to 10 m, but in the case of HDMI and VGA, it should not exceed 5 m. To achieve the maximum transfer rate.

What should I pay attention to when buying a video cable?

To nearby electronic devices do not affect the quality of the transmitted signal, purchase only well-shielded cables. When using a low-quality cable, other devices, creating interference, may even reduce the data transfer rate in some cases. As a result, an intermittent image will be displayed on the screen or an aliasing effect will appear. Gold-plated contacts prevent corrosion of plugs due to high humidity. In addition, the gold-plated contacts used in modern cables reduce the resistance between the connector and the plug, which improves the quality of transmission. But as you can see from practice: all this can be scored, on gold-plated contacts and other lobud, cheap Chinese-made cables, namely, they are supplied complete with monitors and video cards. And they do their job very well.

For reference: somewhere, music lovers were gathered to test cables. They were present with both gold-plated and platinum contacts, from $ 1000 for a lace and much more expensive. Well, the scores were given for sound quality. To determine the winner, the competition was held naturally in the dark, the manufacturer was not visible. Well, some of the organizers came up with the idea to send a signal through an ordinary iron crowbar (with which they hammer the earth). And what do you think, he took one of the prizes.

And music lovers have been explaining for a long time what a crystal clear sound comes through this cool cable. So turn on your head, otherwise I saw the guys have a cable DVI at a price more expensive than the video card and monitor combined.