Monitor with DVI: how to use, trouble

Plug & Play Technology

What is DVI

What is a Digital Visual Interface? This is a special standard for computer and televizonnyh interfaces. The main purpose - to send "pictures" to the electronic device with a display. These devices include projectors, liquid crystal displays, television screens, TV sets. This output is created by Digital Display Working Group.

The overall operation of the technology is as follows - in the video card must "find" the appropriate screen for displaying information at boot time (ON). For operation in the loading mode or debug monitor supporting DVI technology must use the resolution of 640 x 480 pixels and a frequency of 60 Hz.

Resolutions supported by your computer graphics card and the user selected, specifies whether to use the monitor resolution. Those. the user has selected - approved system - the monitor will work with the selected resolution.

At boot time is determined by a digital screen. If all goes well, the active transmission channel "picture" is a TMDS - primary channel type.

A connected secondary support after determining graphics display two-channel system. When connecting the analog type monitor, the computer treats it as the connection on channel D-Sub.

An excursion into history in order to better understand the main principle of DVI technology. The first types of interfaces are digital, these include: EGA, MDA, CGA.

The technology consists of 3 lines for electron guns type + standard type progressive scan control signals. This type of system had a margin in the transmission bandwidth. Such systems lack the technical parameters, for image output, of the time.

analog type interface created by Digital Display Working Group, survived intact about one decade. During this period of modern gadgets and information technologies, has changed a lot.

One of the changes related to the increase of quality resolution screens. The number of pixels has increased four-fold - from 640 to 1280! The changes touched upon the resolution and size of the display used.

In the late 90-ies of the last century, plasma screens have received mass distribution. At the beginning they had a small size and high price. Notebooks got Monitors LCD type.

Plasma displays, laptop screens, used to display graphical information only the digital type signals. The technology was one error that was poor quality color rendering and some delays in the flow.

Return to the transfer of the "picture" via a digital interface proved helpful. This happened in 1999, after the DVI-interface type. The calculation was to preserve the competitiveness of monitors with analog type interface. And a new type of interface includes analog part to preserve the color.

Forms of interface

Digital Visual Interface types:

1. Digital Visual Interface A (Single link) - the transfer of an analog signal;
2. Digital Visual Interface I - digital and analog form;
3. Digital Visual Interface D - transmission of digital type.

Cards with the first type of interface is not supported displays suitable for a third species, and a video card of the second type are suitable for the third type.

The type of information that was used in the Digital Visual Interface interface was based on PanelLink. This data transfer format works on the principle of consistency, and create a company Silicom Image.

The format used in the high speed transmission of digital information technology - Transition Minimized Differential Signaling. Here are 3 channel used for streaming video and other information. Throughput was 3.4 gigabits per second per channel.

Typically, the length of the wire in the DVI specification does not specify. The reason lies in its dependence on the amount of data transmitted. Example: If the cable length is ten and a half meters - it is used for transmission of the "picture", having a resolution up to 1920 pixels.

If the wire length is fifteen meters, it is suitable for the transmission of an image having a resolution of 1280 by 1024 pixels.

The need to enhance the signal for image transmission by cable occurs at greater length of wire. To do this, special devices are used. These devices make it possible to increase the length to a record sixty-one meters.

Single link - it consists of 4 twisted pairs: red, green, blue, clock. They provide a transmission parameter twenty-four bits per pixel. This allows the maximum resolution of 1920 by 1200 pixels at a refresh rate of 60 Hz.

Dual link - DVI to increase data capacity in half. The screen resolution may be 2560 by 1600 pixels. Also, for large LCD displays with high resolution, for example, 30 inches, requires access to the video card with two channels.

After 2008, companies producing video, switched to the production of new The controller for HDMI-interface compatibility to DVI. They elektrosovmestimy and to display information through the Digital Visual Interface HDMI on-device, the TV screen or laptop, using HDMI for audio, requires one simple adapter.

Features technology

Let's start with the disadvantages:

• only supports 24-bit RGB color;
• this technology is not designed for the transmission of sound, with a few exceptions;
• Advanced HDMI give odds outdated DVI, however, and it costs more.

Differences between the two interfaces abound. It begins with the appearance of the connectors. DVI larger rival, there are a lot of cells, has the special screws for fastening, looks solid.

Both interfaces similar connection methods, the reason for this - the use of digital signal TMDS technology. Due to the application of this technology, both can be interconnected through a conventional adapter. Data quality is the same for both interfaces to the wire similar requirements.

Despite their differences, these interfaces are not competitors, they are - for different applications and are designed for multiple market segments. DVI - for PCs and professional equipment, and HDMI - for household appliances.

The HDMI audio transmission opportunity provided - 8-channel audio. But in no way HDMI provides an analog signal transmission. A two-channel HDMI are extremely rare.

Problems

In recent years, there are many devices with DVI-interface. Later came HDCP, compatible with DVI-HDTV. In those days, when the connector for external were similar to each other, it was impossible to understand what the output uses a particular device.

If the buyer acquires a model without HDCP support, he could get a device that is not able to play back the data. And today, this problem may occur. The fact is that while the source is required to make a request to the display, to obtain data on a supported format.

This simple method gives a chance to find a suitable option to display images. But in this case, not everything is so smooth - the process can not "get" in the optimal settings of the monitor.

Problems on devices can occur using the same DVI formats. There are a huge number of other factors:

• the difference in the form of cards or chips;
• the technical condition of the cables for connecting the devices.

A common problem is the appearance of red dots around the display with a high resolution.

The reasons for this are as follows:

1. Insufficient contact cables;
2. Weak protection of wire or strong interference;
3. Insufficient capacity.

Consider ways to solve:

1. improved fastener wire in a nest at the expense of tightening screws on the forks;
2. replacement is carried out with antijamming;
3. replacing wires on Dual link;
4. reduction in the frequency of the video card driver updates;
5. Mode switch in the DVI .;
6. increase in interference suppression in the Nvidia company.

We should not forget about the length of the wire. This factor carries critical to quality "pictures". The length of wire should be selected based on the frequency synchronization in the display (pixel) and the selected video format. In some cases, the use of 20-meter wire gives a better image than 2 m.

And found a new solution to this problem - EQ chips adaptive species, cable, adjust the signal, taking into account characteristics. Given the difference in synchronizing frequency and level as the wires, they are able to transmit a signal to 30-50 meters. That's enough for home use. Such chips will reduce customer costs.

How to use a monitor with a DVI

When using the monitor with DVI-interface, remember some rules of operation:

1. Not worth looking not pull out the wire from the connector: it may be damaged, or socket, and use the device to become the former regime impossible.
2. It is important to monitor the condition and the inner side of the interface: clean dust and be careful with the teeth, which are easily damaged by careless use of wires.
3. If the wire is short, you can not stretch too much: one day monitor "go" down the cable if someone steps on it or pull too hard.