DVI is an interface standard and a corresponding connector used to transmit video images to digital display devices such as LCD monitors, televisions, and projectors.
Since the signal transmitted over the DVI cable is digital and does not need double conversion, the maximum length of the cable used should not exceed 5 meters.
The DVI video interface can be of two types 24-pin and 29-pin.
DVI-D 24-pin is designed for digital interface. Only a digital code is sent to its pins
DVI-I 29-pin connector differs in that it also supports analog signal transmission
The VGA connector is an outdated analog interface designed in 1987 for connecting analog monitors, but is still in use today.
VGA - Transmits three chrominance, luminance and sync signals. Its pinout and the purpose of each pin:
Knowing the pinout of these connectors, you can easily solder a DVI-VGA or VGA-DVI adapter.
Composite video input / output (RCA), this is an analog video input - output, is widely used in video technology as a universal switching tool. Often referred to as "Asian" or "Tulip". Almost two separate coaxial connectors, they can be seen on the back of almost any VCR, TV, DVD player. The standard is purely analog, transmits a standard composite video signal. The main advantage of the interface is simplicity and low cost. The chrominance and luminance signals are transmitted over the same wire. This does not allow to achieve a very clear image, so the real resolution is in the region of 250 -280 lines. The maximum cable length can be 20-30 meters.
These connectors can be present in a PC on a video card or an internal TV tuner board for receiving and transmitting an analog signal, for sending a picture to the screen of a conventional TV, for recording the generated video signal to a VCR, for transmitting a signal from an analog video signal source to a video capture card.
S-Video (or S-VHS) is another analog connector widely used in video technology today. The chrominance and brightness signals go through separate cores, and do not interfere with each other at all. Therefore, a picture with a resolution of 400-500 lines can be obtained.
Good day.
One of the most common questions when connecting a monitor to a computer is to deal with the variety of connectors, make the right choice of cable so that everything works. (especially difficult if the monitor has several interfaces at once). Whether it was before, there is one VGA everywhere: everything is simple and clear. But over time (after the appearance of monitors with high resolutions), its capabilities became insufficient, and new interfaces began to appear...
In general, now on monitors you can most often find DVI, Display Port or HDMI interfaces. Moreover, they are all in turn subdivided into several more types (if I may say so). The situation is even more complicated if there are some interfaces on the monitor, and completely different ones on the PC. It's no wonder to get confused...
In this article I will try to "disassemble" this whole tangle, and answer the typical and most frequent questions on this problem.
And so, more to the point ...
HDMI
One of the most demanded and popular interfaces today. It is found on the vast majority of laptops and computers (it can also often be found on tablets). Suitable for connecting monitors, TV (and set-top boxes), projectors and other video equipment.
Peculiarities:
- transmits both audio and video signals (simultaneously). In this regard, this is a big plus for the interface: no extra cables are needed to transmit an audio signal;
- full support for FullHD (1920x1080) resolutions, with 3D effects. The maximum supported resolution is up to 3840×2160 (4K);
- the cable length can be up to 10 meters, which is sufficient in most cases (with the use of repeater amplifiers - the cable length can be increased up to 30 meters!);
- has a bandwidth of 4.9 (HDMI 1.0) to 48 (HDMI 2.1) Gb / s;
- on sale there are adapters from HDMI to DVI and vice versa (very important for the compatibility of old and new devices with each other);
- HDMI has several types of connectors: HDMI (Type A), mini-HDMI (Type C), micro-HDMI (Type D) (see photo above). On laptops/PCs, the most commonly used classic size type is HDMI (Type A). Micro and Mini are found in portable technology (in tablets, for example).
If you have HDMI on your monitor and system unit (laptop), then the whole connection will come down to buying an "HDMI-HDMI" cable (which you can buy at any computer store).
I draw your attention to the fact that before connecting via HDMI, be sure to turn off both devices (both the PC and the monitor). if this is not done.
display port
A new interface that is rapidly gaining popularity (a competitor to HDMI). Allows you to connect multiple monitors at once, supports 4K resolution, 3D image. There are two sizes: classic and Mini Display Port (the first option is found on regular laptops and monitors, see photo above).
Peculiarities:
- both audio and video signals are transmitted simultaneously;
- the maximum length of the Display Port cable can be up to 15 meters;
- data transfer rate up to 21.6 Gbps;
- allows you to get a resolution of up to 3840 x 2400 at 60 Hz; or 2560 x 1600 dots at 165 Hz; or you can connect two monitors at once with a resolution of 2560 x 1600 pixels and a frequency of 60 Hz.
- Please note that in addition to the classic Display Port, there is another form factor: Mini Display Port.
- By the way, the size of the Mini Display Port connector is about 10 times smaller than that of the DVI connector (more on that in the article below)!
- the interface has a small "latch" that securely fixes the cable when connected to the port.
DVI
This interface is almost 20 years old, and is still very popular (released in 1999). At one time, seriously improved the quality of the image on the screen.
The maximum resolution is 1920 x 1080 pixels (however, some expensive video cards can transfer data in dual link mode and the resolution can reach 2560 x 1600 pixels).
Peculiarities:
- only the image is transmitted through the DVI connector (the audio signal will have to be transmitted via other channels);
- resolution up to 1920×1200 pixels with cable length up to 10.5 m; resolution 1280×1024 pixels with cable length up to 18 m; in dual-channel data transmission mode - up to 2560 x 1600 pixels.
- There are three types of DVI: DVI-A Single Link - analog transmission; DVI-I - analog and digital transmissions; DVI-D - digital transmission.
- various connectors and their configuration (DVI-A, DVI-D, DVI-I) are compatible with each other.
- Please note that interference is more likely to occur with this standard: for example, if there are other devices that emit an electromagnetic signal (telephone, printer, etc.) near the cable. Also, this can happen due to poor cable shielding;
- on sale there are many adapters from VGA to DVI and vice versa;
- the DVI connector is large enough, ~10 times larger than the Mini Display Port (Apple even released Mini DVI, but it didn't find much popularity...).
VGA (D-Sub)
This standard was developed back in 1987. Despite this, it is still very popular, it is used mainly for simple projectors, video set-top boxes, small office monitors (where high resolution and very high-quality images are not required). Officially supported resolution is up to 1280×1024 pixels, and therefore many "prophesy" an early eclipse of this interface...
My personal opinion: many people "bury" this interface early, because thanks to hundreds of millions of devices that have been released over these 30 years, VGA will "survive" some modern ones.
Peculiarities:
- transmits only video signal (for audio it is necessary to use other channels);
- maximum resolution up to 1280×1024 pixels, at a frame rate of 75 Hz (in some cases it is possible to work at a higher resolution, but this is not officially guaranteed, and the image quality may also deteriorate);
- there are many adapters VGA to HDMI, VGA to Display Port, VGA to DVI and vice versa;
- despite the "moral" obsolescence - the interface is supported by a variety of audio and video equipment, and is still in great demand.
Popular questions about connecting and choosing a cable
Option 1: The monitor and computer have the same interface (HDMI or Display Port)
Perhaps this is the most favorable option. In general, it is enough to buy a standard HDMI cable (for example), connect devices with it and turn them on. No additional setup is required: the image is immediately displayed on the monitor.
Important!
If the HDMI connection is "hot", the port may burn out! How to avoid this, and what to do (if the monitor / TV via HDMI does not work) is described in this instruction:
Option 2: devices have different interfaces. For example, on an HDMI laptop, on a VGA monitor.
This option is more complicated... Here, in addition to the cable, you need to buy a special adapter (sometimes the cost of such adapters reaches 30% of a new monitor!). It is better to buy both the cable and the adapter as a set (from the same manufacturer).
Also note that old PCs/laptops with VGA|DVI connectors may simply not "give out" a high resolution picture if you want to connect a large monitor/TV to them.
There are a lot of adapters on sale now that provide interaction between different interfaces (VGA, Display Port, HDMI, DVI).
What if I take different versions of the HDMI connector
If you mean the form factor - that is. Micro and classic size connectors, then you need a special to connect them. cable (possibly an adapter).
If we are talking about connecting a video card that supports the HDMI 1.4 standard (with 3D), say, to a monitor with HDMI 1.2, then the devices will work according to the HDMI 1.2 standard (without 3D support).
Does cable length matter? Which interface do you prefer?
Yes, cable length matters a lot. The longer the cable, the weaker the signal, the greater the likelihood of various interferences, etc. Say, in the general case, it is undesirable that its length exceeds 1.5 ÷ 3 m.
Of course, the interface you choose also affects the length. For example, the HDMI interface allows you to use a cable up to 10 meters long (and up to 25-30 meters with an amplifier!). While the same VGA - cable longer than 3 m can significantly "spoil" the picture.
As for quality, today one of the best pictures is provided by HDMI and Display Port (resolution up to 4K, while transmitting an audio signal, and with almost no interference).
Classic USB and USB Type C
By the way, on new laptops and PCs you can find USB Type C connector . Of course, it has not yet been widely used, but it looks promising. Allows you to "hot" connect the monitor to a PC, while audio-video signals are transmitted. In some cases, the monitor does not even need additional power - the power from the USB port is enough.
You may find the article on how to properly connect a monitor to a laptop (step by step instructions) - useful.
That's all for today, good luck everyone!
There are many ways to display a video image on a monitor or TV today - there are more and more port options for connecting every year, and it is not surprising to get confused in the number and difference of interfaces.
Let's look at the most popular formats and determine the cases when one or another video port standard is best suited.
VGA
The oldest of the PC-to-monitor pairing standards that still exists today. Developed back in 1987 by IBM, the component video interface uses an analog signal to transmit color information. Unlike more modern standards, VGA does not allow you to transmit sound - only a picture.
The VGA connector is usually blue with two screws on the sides. It has a 15-pin connector and initially could only work at 640 by 480 pixels using a palette of 16 colors. Later, the standard evolved into the so-called Super VGA, supporting higher screen resolutions and up to 16 million colors. And since the improved standard continued to use the old port and did not change outwardly, they call it the old fashioned way simply VGA.
This format is most commonly used on older hardware, but many computers still have this port. What is called - just in case.
DVI
More than ten years after the release of the VGA standard, the DVI format, a digital video interface, saw the light of day. Released in 1999, the interface was capable of transmitting video without compression in one of three modes: DVI-I (Integrated) - a combined digital and analog transmission format, DVI-D (Digital) - support for only a digital signal, DVI-A (Analog ) – support for analog signal only.
The DVI-I and DVI-D ports can be in single mode or dual mode. In the second case, the bandwidth is doubled, which allows you to get a high-definition screen resolution - up to 2048 by 1536 pixels. However, for this you need to have an appropriate video card. The ports themselves differ in the number of pins - so single mode (Single link) uses four twisted pairs of wires (maximum resolution 1920 by 1200 pixels at 60 Hz), and dual mode (Dual link), a correspondingly larger number of pins and wires (resolution up to 2560 by 1600 at 60 Hz).
It is important to remember that analog DVI-A does not support DVI-D monitors, and a video card with DVI-I can be connected to a DVI-D monitor with a cable with two DVI-D-male connectors. By analogy with VGA, this standard also transmits only the video image without sound to the screen. However, since 2008, video card manufacturers have made sound transmission possible - for this you need to use a DVI-D - HDMI cable.
You can also find the mini-DVI format on the market, invented by Apple, which is prone to reducing everything and everything. However, the mini-standard works only in single mode, which means it does not support resolution higher than 1920 by 1200 pixels.
HDMI
The High Definition Multimedia Interface or interface for high-definition multimedia allows the transmission of digital video and audio signals, and even with the possibility of copy protection. HDMI is smaller than its predecessors, operates at a higher speed, and, most importantly, transmits sound, which made it possible to retire the old SCART and RCA (“tulips”) standards for connecting video devices to TVs.
The HDMI 1.0 specification appeared at the end of 2002 and had a maximum bandwidth of 4.9 Gb / s, support for 8-channel audio and video up to 165 MPix / s (i.e. FullHD at 60 Hz). Since then, the standard has been constantly evolving, and in 2013, the HDMI 2.0 specification was released with a bandwidth of up to 18 Gb / s, support for 4K resolution (3840 by 2160 pixels at 60 Hz) and 32-channel audio.
Today, the HDMI standard is used not only by computers, but also by digital TVs, DVD and Blu-ray players, game consoles and many other devices. If desired, you can use adapters from HDMI to DVI and vice versa.
The number of pins on HDMI ports starts from 19, and the connectors themselves are available in several form factors, the most common of which are HDMI (Type-A), mini-HDMI (Type-C), micro-HDMI (Type D). In addition, there are HDMI ports for signal reception (HDMI-In) and transmission (HDMI-Out). Outwardly, they are almost indistinguishable, but if, say, your monoblock has both ports, then when you try to display a picture on a second monitor, you can use only one of them, namely HDMI-Out.
display port
In 2006, another video standard for digital monitors was adopted. DisplayPort, like HDMI, transmits not only video, but also audio, and is used to connect a computer with a display or home theater. DisplayPort has a higher data rate, support for resolutions up to 8K (7680 by 4320 pixels at 60 Hz) in version 1.4, released in March 2016, and the image through the port can be displayed on multiple monitors (from two to four, depending from permission).
DisplayPort was specifically designed to output images from computers to monitors, while HDMI was more intended for connecting various devices to a TV. However, these ports can be used together using a Dual-Mode DisplayPort adapter.
There are also variations of Mini DisplayPort, primarily used in laptops. In particular, the reduced format is loved by Apple.
Thunderbolt
Finally, a standard from Intel (in collaboration with Apple) for connecting peripherals to a computer. It was Apple who was the first to release a device with this interface in 2011 - the MacBook Pro laptop.
The maximum data transfer rate is 20 Gb / s when using fiber for version 2, while the 3rd version of the interface is capable of operating at speeds up to 40 Gb / s. Thunderbolt combines not only the DisplayPort interface, but also PCI-Express, which means you can connect almost anything to it. In particular, up to six devices can be connected to one port, which reduces the need for a huge number of different ports on a device.
The Thunderbolt connector itself is smaller than the mini-DisplayPort, and its third version is a USB 3.1 compatible port, that is, it is made with a USB Type-C connector.
Universal USB
If you are suddenly worried that you will soon have to update all home appliances due to changing standards, then do not rush. Manufacturers are looking to simplify the story with multiple interfaces and provide support for older devices through adapters. In particular, for HDMI devices, you will only need to use the appropriate adapter in order to be able to connect to a modern USB Type-C port.
Similar to the fact that in the past each mobile phone manufacturer had its own charging port, and now most use the micro-USB port, the video standard is also striving for unification. And the unifying form factor should be exactly the latest generation USB port, through which both monitors and regular headphones and headsets will be connected.
This article will be useful to those who are thinking about purchasing a new monitor or replacing an old video adapter. The monitor connector may not be compatible with the available graphics adapter interfaces. In addition, the quality of the image depends on the type of connector, and each type of cable has its own critical length.
Previously, it was enough to connect a VGA connector to a computer monitor. Today, interfaces such as DVI, HDMI, DisplayPort come into everyday life. Each of them has its own advantages and disadvantages, which should be considered when upgrading a PC. You should know everything about the monitor connector: types, adapters, connection.
1. VGA (Video Graphics Array) connector- an analog standard designed for monitors with a resolution of 640 * 480. As the resolution increases, the quality of the digital image deteriorates. Digital standard connectors are required for high quality images.
2. Digital interface DVI (Digital Visual Interface) transmits a video signal in digital format and provides high quality digital images. The interface is compatible with an analog VGA connector (transmits a signal in both digital and analog format at the same time). Inexpensive video cards are equipped with a DVI output with a single-channel modification (Single Link). In this case, the monitor resolution is 1920*1080. More expensive models are equipped with a dual-channel interface (Dual Link) and can support resolutions up to 2560*1600. A mini-DVI interface has been developed for the laptop.
3. HDMI (High Definition Multimedia Interface) Digital Multimedia Interface most commonly used in home entertainment devices (flat-panel TVs, blu-ray players). The monitor connector also retains the high quality of the original signal. Together with this interface, a new HDCP technology was developed, which protects content from exact copying, for example, the same video materials.
Since 2003 (the year of creation), the interface has been modified several times, adding support for video and audio formats. A miniaturized interface has been created for small vehicle models. They come with many devices.
4. Display Port (DP)- a new digital interface designed to connect graphics adapters with display devices. The current version allows the connection of multiple monitors, provided they are connected in series in a chain.
At the moment, there are few devices with such a port, but DP has a great future. Its advanced DP++ model (this designation can be seen on laptop or computer connectors) allows you to connect monitors with HDMI or DVI interfaces.
5. USB (3.0) : USB connection became possible when high-speed version 3.0 was released. Using a DisplayLink adapter, you can connect a DVI/HDMI monitor to a USB port on a laptop or computer.
How to "fit" the monitor and video card connector?
The most common affordable adapter today is DVI-I / VGA. There are converters that convert the output digital signal to analog (for example, DisplayPort / VGA), but this option will cost much more.
However, there is something else to consider when choosing an adapter. Some of them deprive the existing interface of some advantages. For example, if you connect the HDMI connector of a monitor or TV to the DVI connector, there will be no sound.
Feature of connector versionshdmi
When docking devices with different versions of HDMI interfaces, the devices will only perform the functions of the earlier version. For example, if you connect a 3D TV with HDMI version 1.4 to a video card with HDMI 1.2, all 3D games will only be displayed in 2D.
If this situation has arisen, you can replace the driver on the video card with a newer one. Using the 3DTV Play program, you can display 3D graphics on your own TV.
Which monitor connector should I choose?
According to testing, VGA interfaces show the lowest display quality. For a monitor with a diagonal of more than 17 inches and a resolution of more than 1024 * 786, it is recommended to use DVI, HDMI, DisplayPort connectors.
How to connect monitor and laptop?
To connect a laptop to an external monitor, you must use the available connectors. After that, it will be possible, using the combination of buttons "Fn + F8", to switch between the following modes.
You can use an external monitor as main. In this case, the image will be displayed only on an external monitor, and the picture will be completely absent on the laptop display (convenient for watching movies).
You can use an external monitor in clone mode, i.e. the same image will be displayed both on the laptop screen and on an external monitor / TV (convenient for seminars and presentations).
Multi-screen mode allows you to increase the size of the desktop (stretch) using multiple monitors (handy when typing and viewing messages).
Maximum cable length
The length of the cable depends on the type of connection. For DVI-DVI connections, the maximum allowed cable length is 10 m. For DVI-HDMI connections, no more than 5 m. For DisplayPort connections, no more than 3 m. Following these requirements will help you get the maximum data transfer rate. If you want to transmit information over a longer distance, you will have to resort to using a signal amplifier.
When buying a video cable, you should choose well-shielded models. This will help to avoid the negative impact of nearby electronic devices on the quality of the transmitted video signal. If you use a low quality cable, the video data transfer rate may slow down. Which, in turn, can lead to the appearance of an intermittent image on the screen (aliasing). 
You should pay attention to the presence of gold-plated contacts in the monitor connector. They counteract the appearance of corrosion in places with high humidity. In addition, such contacts reduce the resistance between the plug and the socket, thereby improving the quality of data transmission.
Modern computers have ample opportunities for working with video, and their owners often watch movies on the monitor screen. And with the advent of barebone multimedia platforms, oriented to use as a home media center, the interest in connecting audio and video equipment only intensifies.
It is much more convenient and practical to watch video on a large TV screen, especially since almost all modern video cards are equipped with a TV output.
The need to connect a TV to a computer also arises when editing amateur video. As you can easily see in practice, the image and sound on the computer are significantly different from those that you will later see and hear on TV. Therefore, all video editors allow you to view the preliminary results of editing on a television receiver directly from the working scale even before the film is created. Experienced video enthusiasts constantly control the image and sound, displaying them on a television screen, and not on a computer monitor.
Topics such as setting up video cards, choosing an image standard, as well as comparing the quality of video outputs of video cards from different manufacturers and solving the problems that arise in this case are beyond the scope of this article - here we will only consider the following questions: what connectors can be found on a TV and on a video card, how they are consistent with each other and what are the ways to connect a computer to a TV.
Display interfaces
Classic analog interface (VGA)
Computers have been using the 15-pin analog D-Sub HD15 (Mini-D-Sub) interface for quite a long time, which is traditionally called the VGA interface. The VGA interface transmits red, green, and blue (RGB) signals as well as horizontal (H-Sync) and vertical synchronization (V-Sync) information.
All modern video cards have such an interface or provide it using an adapter from the universal combined DVI-I (DVI-integrated) interface.
Thus, both digital and analog monitors can be connected to the DVI-I connector. A DVI-I to VGA adapter is usually included with many graphics cards and allows you to connect older monitors with a 15-pin D-Sub (VGA) plug.
Please note that not every DVI interface supports analog VGA signals, which can be obtained through such adapters. Some graphics cards have a DVI-D digital interface to which you can connect only digital monitors. Visually, this interface differs from DVD-I in the absence of four holes (pins) around the horizontal slot (compare the right parts of the white DVI connectors).
Often modern graphics cards are equipped with two DVI outputs, in which case they are usually universal - DVI-I. Such a video card can simultaneously work with any monitors, both analog and digital in any set.
DVI digital interface
The DVI interface (TDMS) was developed primarily for digital monitors that do not require the graphics card to convert digital signals to analog.
But since the transition from analog to digital monitors has been slow, graphics hardware designers typically use these technologies in parallel. In addition, modern video cards can work with two monitors at the same time.
The universal DVI-I interface allows you to use both digital and analog connections, while DVI-D only allows you to use digital. However, the DVI-D interface is quite rare today and is usually used only in cheap video adapters.
In addition, DVI digital connectors (both DVI-I and DVI-D) have two varieties - Single Link and Dual Link, which differ in the number of pins (Dual Link uses all 24 digital pins, and Single Link uses only 18 ). Single Link is suitable for use in devices with resolutions up to 1920x1080 (full HDTV resolution), for about Higher resolutions require Dual Link, which allows you to double the number of displayed pixels.
HDMI digital interface
HDMI (High Definition Multimedia Interface) is a digital multimedia interface developed jointly by a number of major companies - Hitachi, Panasonic, Philips, Sony and others. ). Higher resolution video requires already 29-pin Type B connectors. In addition, HDMI can provide up to eight channels of 24-bit, 192 kHz audio and has built-in Digital Rights Management (DRM) copyright protection.
The HDMI interface is relatively new, but in the computer sector it has quite a few competitors - both from the traditional DVI interface and from newer and more advanced interfaces such as UDI or DisplayPort. However, products with HDMI ports are gradually moving into the market, as modern consumer video equipment is increasingly equipped with HDMI connectors. Thus, the growing popularity of multimedia computing platforms will stimulate the emergence of graphics and motherboards with HDMI ports, even though computer manufacturers have to buy a rather expensive license to use this standard and still pay some flat royalties on each product sold with an HDMI interface. .
The licensing fees also make products with HDMI ports more expensive for the end-manufacturer - for example, a video card with an HDMI port will cost about $10 more. In addition, it is unlikely that an expensive HDMI cable ($10-30) will be included in the package, so you will have to purchase it separately. However, there is hope that as the popularity of the HDMI interface grows, the size of such a premium will gradually decrease.
The HDMI interface uses the same TDMS signal technology as DVI-D, so inexpensive adapters are available for these interfaces.
And while the HDMI interface has not yet replaced DVI, such adapters can be used to connect video equipment via the DVI interface. Please note that HDMI cables cannot be longer than 15m.
New UDI interface
At the beginning of this year, Intel announced a new UDI (Unified Display Interface) digital interface for connecting digital monitors to a computer. So far, Intel has only announced the development of a new type of connection, but in the near future it plans to completely abandon the old analog VGA interface and connect computers to information display devices through a new UDI digital interface recently developed by engineers from this company.
The creation of a new interface is due to the fact that both the analog VGA interface and even the digital DVI interface, according to Intel representatives, are hopelessly outdated today. In addition, these interfaces do not support the latest content protection systems found on next-generation digital media such as HD-DVD and Blu-ray.
Thus, UDI is almost analogous to the HDMI interface used to connect computers to modern HDTVs. The main (and perhaps the only) difference between UDI and HDMI will be the absence of an audio channel, that is, UDI will only transmit video and is entirely designed to work with computer monitors, and not with HD TVs. Also, Intel doesn't seem to want to pay royalties for every HDMI device it makes, so UDI would be a good alternative for companies looking to make their products cheaper.
The new interface is fully compatible with HDMI, and will also support all currently known content protection systems, allowing seamless playback of new media equipped with copy protection.
New DisplayPort Interface
Another new video interface - DisplayPort - has recently received approval from companies that are members of the VESA (Video Electronics Standards Association).
The open DisplayPort standard has been developed by a number of major companies, including ATI Technologies, Dell, Hewlett-Packard, nVidia, Royal Philips Electronics, and Samsung Electronics. It is assumed that in the future DisplayPort will become a universal digital interface that allows you to connect displays of various types (plasma, liquid crystal, CRT monitors, etc.) to household devices and computer equipment.
The DisplayPort 1.0 specification provides for the possibility of simultaneous transmission of both video and audio streams (in this sense, the new interface is completely similar to HDMI). Note that the maximum throughput of the DisplayPort standard is 10.8 Gbps, and the transmission uses a relatively thin four-conductor connecting cable.
Another feature of DisplayPort is its support for content protection features (similar to HDMI and UDI). Built-in security controls allow the content of a document or video file to be displayed only on a limited number of "authorized" devices, theoretically reducing the chance of illegal copying of copyrighted material. Finally, connectors made according to the new standard are thinner than modern DVI and D-Sub connectors. Thanks to this, DisplayPort ports can be used in small form factor equipment and easily make multi-channel devices.
Support for the DisplayPort standard has already been announced by Dell, HP and Lenovo. Apparently, the first devices equipped with new video interfaces will appear before the end of this year.
Video connector on graphics card
On modern video cards, in addition to connectors for connecting monitors (analog - D-Sub or digital - DVI), there is a composite video output ("tulip"), or a 4-pin S-Video output, or a 7-pin combined video output ( both S-Video and composite inputs and outputs).
In the case of S-Video, the situation is simple - there are S-Video cables or adapters for other SCART connectors on sale.
However, when a non-standard 7-pin connector is found on video cards, then in this case it is better to keep the adapter that is included with the video card, because there are several standards for wiring such a cable.
Composite video signal (RCA)
The so-called composite video output has long been widely used to connect consumer audio and video equipment. The connector for this signal is usually referred to as RCA (Radio Corporation of America), and is popularly called a "tulip" or VHS connector. Please note that such plugs in video equipment can transmit not only composite video or audio, but also many other signals such as component video or high-definition television (HDTV). Typically, tulip plugs are color-coded to make it easier for users to navigate the tangle of wires. Common color values are given in Table. one.
Table 1
|
Usage |
Signal type |
|
|
White or black |
Sound, left channel |
analog |
|
Sound, right channel |
analog |
|
|
Video, composite signal |
analog |
|
|
Luminance component signal (Luminance, Luma, Y) |
analog |
|
|
Component Chroma (Chrominance, Chroma, Cb/Pb) |
analog |
|
|
Component Chroma (Chrominance, Chroma, Cr/Pr) |
analog |
|
|
orange/yellow |
SPDIF digital audio |
Digital |
The wires for transmitting a composite signal can be quite long (simple adapters can be used to extend the wires).
However, the use of low quality connections and sloppy switching "tulips" is gradually becoming a thing of the past. In addition, cheap RCA connectors on equipment often break. Today, other types of switching are increasingly used on digital audio and video equipment, and even when transmitting analog signals, it is more convenient to use SCART.
S-video
Often on the video card and on the TV there is a four-pin S-Video (Y / C, Hosiden) connector, which is used to transmit video signals of higher quality than composite. The fact is that the S-Video standard uses different lines for transmitting brightness (the signal for brightness and data synchronization is denoted by the letter Y) and color (the color signal is denoted by the letter C). Separation of luminance and color signals allows to achieve better picture quality in comparison with the composite RCA-interface ("tulip"). Higher quality when transmitting analog video can only be provided by completely separate RGB or component interfaces. To receive a composite signal from S-Video, a simple S-Video to RCA adapter is used.
If you do not have such an adapter, then you can make it yourself. However, there are two options for outputting a composite signal from a video card equipped with an S-Video interface, and the choice depends on the type of video card you have. Some cards are able to switch output modes and feed a simple composite signal to the S-Video output. In the mode of supplying such a signal to S-Video, you simply need to connect the contacts to which the composite signal is applied to the corresponding "tulip" outputs.
The wiring of the RCA cable is simple: a video signal is fed through the central core, and the outer braid is the “ground”.
The S-Video pinout is as follows:
- GND - "ground" for the Y-signal;
- GND - "ground" for the C-signal;
- Y - brightness signal;
- C - color signal (contains both color differences).
If the S-Video output can operate in the composite signal supply mode, then a ground is supplied to the second pin of its connector, and a signal to the fourth. On a collapsible S-Video plug, which is required to make an adapter, the contacts are usually numbered. The socket and plug connectors are numbered in reverse order.
If the video card does not have a composite signal output mode, then to obtain it, you will have to mix the color and brightness signal from the S-Video signal through a 470 pF capacitor. The signal obtained in this way is fed to the central core, and the "ground" from the second contact is fed to the braid of the composite cord.
SCART
SCART is the most interesting combined analog interface and is widely used in Europe and Asia. Its name comes from the French abbreviation proposed in 1983 by the Association of Radio and Television Developers of France (Syndicat des Constructeurs d'Appareils, Radiorecepteurs et Televiseurs, SCART). This interface combines analog video (composite, S-Video and RGB), stereo audio and control signals. Today, every television or VCR manufactured for Europe is equipped with at least one SCART socket.
For the transmission of simple analog signals (composite and S-Video), there are many different SCART adapters on the market. This interface is convenient not only because everything is connected using only one cable, but also because it allows you to connect a high-quality RGB video source to the TV without intermediate encoding into composite or S-Video signals and get the best image quality on the home TV screen (image and sound quality via SCART is noticeably superior to any other analog connections). This possibility, however, is not implemented in all VCRs and TVs.
In addition, the developers have incorporated additional features into the SCART interface, reserving a few contacts for the future. And since the SCART interface has become the standard in European countries, it has acquired several new features. For example, with the help of some signals on pin 8, you can control the TV modes via SCART (transfer it to the “monitor” mode and vice versa), switch the TV to work with RGB signals (pin 16), etc. Pins 10 and 12 are dedicated to transmitting digital data via SCART, which makes the number of commands virtually unlimited. There are several known systems for exchanging information via SCART: Megalogic, used by Grundig; Easy Link from Philips; Smart Link from Sony. True, their use is limited to communication between a TV and a VCR of these companies.
By the way, the standard provides for four types of SCART cables: type U - universal, providing all connections, V - without audio signals, C - without RGB signals, A - without video signals and RGB. Unfortunately, modern component modes (Y, Cb/Pb, Cr/Pr) are not supported in the SCART standard. However, some manufacturers of DVD players and large format TVs build in the ability to transmit via SCART and component video, which is transmitted through the pins used in the RGB signal standard (however, this capability is practically the same as connecting via RGB).
Various adapters are commercially available for connecting composite or S-Video sources to SCART. Many of them are universal (bidirectional) with an input-output switch.
There are also simple unidirectional adapters, adapters for connecting mono or stereo audio, and connectors for switching control. In the case when it is necessary to connect two devices at once to one device, you can use a SCART splitter in two or three directions. Those who are not satisfied or who are not available to the proposed options can make their own in accordance with the assignment of contacts in SCART, given in Table. 2.
The pin numbering is usually indicated on the connector:
Of course, computers do not use a SCART connector, however, knowing its specification, you can always make an appropriate adapter to use an analog computer monitor as a video signal receiver from a tape recorder or, conversely, to feed a video signal from a computer to a TV equipped with a SCART connector.
For example, in order to input or output a composite signal from a SCART connector, you need to take a coaxial cable with a characteristic impedance of 75 ohms and distribute the outer braid (“ground”) and the inner core (composite signal) on the SCART connector.
Outputting a video signal from a computer to a TV (TV-OUT):
- the composite signal is fed to the 20th pin of the SCART connector;
To input video from a VCR to a computer (TV-IN):
- composite signal - to the 19th pin of the SCART connector;
- "ground" - on the 17th pin of the SCART connector.
The correspondence of contacts in the manufacture of an adapter for S-Video is also indicated in Table. 2.
Video output from a computer to a TV set via S-Video (TV-OUT):
- 3rd pin S-Video - 20th pin SCART;
Inputting video signal from a VCR to a computer via S-Video (TV-IN):
- 1st pin S-Video - 17th pin SCART;
- 2nd pin S-Video - 13th pin SCART;
- 3rd pin S-Video - 19th pin SCART;
- 4th S-Video pin - 15th SCART pin.
To connect a computer to a TV using RGB, the computer must output the RGB signal in a way that the TV can understand. Sometimes the RGB signal is fed through a dedicated 7-, 8-, or 9-pin combo video output. In this case, in the settings of the video card, it should be possible to switch the video output to RGB mode. If the video output on the video card has seven pins (such a plug is called a mini-DIN 7-pin), then in normal mode the S-Video signal is sent to exactly the same pins as in a regular four-pin S-Video connector. And in RGB mode, the signals on the pins can be distributed in different ways, depending on the manufacturer of the video card.
As an example, the pins of one of these 7-pin connectors correspond to SCART (this wiring is used on some video cards based on the NVIDIA chip, but it may be different on your video card):
- 1st pin mini-DIN 7-pin (GND, "ground") - 17th pin SCART;
- 2nd pin mini-DIN 7-pin (Green, green) - 11th pin SCART;
- 3rd pin mini-DIN 7-pin (Sync, sweep) - 20th pin SCART;
- 4th pin mini-DIN 7-pin (Blue, blue) - 7th pin SCART;
- 5th pin mini-DIN 7-pin (GND, "ground") - 17th pin SCART;
- 6th pin mini-DIN 7-pin (Red, red) - 15th pin SCART;
- 7th mini-DIN 7-pin (+3 V RGB mode control) - 16th SCART pin.
For all types of adapters, it is required to use high-quality cables with a resistance of 75 ohms.
Graphics card does not have a video connector
If your video card does not have a TV output, then, in principle, the TV can be connected to a regular VGA connector. However, in this case, an electrical signal matching circuit will be needed (in the general case, however, it is simple). There are special devices on the market that convert a regular computer VGA signal into RGB and into a scan (synchronization) signal for a TV. Such a device is connected to the VGA cable between the computer and the monitor and duplicates the signal that goes through the VGA output.
In principle, such a device can be made independently. The correspondence between VGA and SCART signals will be as follows:
- VGA SCART PIN SCART Description;
- VGA RED - to the 15th SCART pin;
- VGA GREEN - on the 11th SCART pin;
- VGA BLUE - on the 7th SCART pin;
- VGA RGB GROUND - on the 13th, or 9th, or 5th SCART pin;
- VGA HSYNC & VSYNC - on the 16th and 20th SCART pins.
You will also need to apply +1-3 V to the 16th SCART pin and 12 V to the 8th SCART pin to switch to AV mode with an aspect ratio of 4:3.
However, a direct connection will most likely not work and you will need to make a wiring diagram for synchronization, as shown at http://www.tkk.fi/Misc/Electronics/circuits/vga2tv/circuit.html or http://www.e.kth .se/~pontusf/index2.html .
