Good to know: What is DVI?

DVI - The Digital Video Interface

The Digital Display Working Group, which was made up of companies including Intel, Fujitsu and IBM, is responsible for the publication of the DVI connection in 1999. The acronym DVI stands for Digital Video Interface and the interface was the first widespread standard that could transmit images digitally between a graphics card and monitor. Previously, there was only the purely analog VGA interface.

Advantages of DVI

As mentioned in the previous paragraph, DVI transmits images digitally. For this reason, the process of converting analog to digital images, as used to be the case with VGA, is no longer necessary and the images can be transferred directly from the graphics card to the monitor without any loss of quality.

Data transmission with DVI

DVI uses the TMDS standard for digital data transmission. This converts the three color channels into just one serial signal with three channels. As the clock rate is limited to 165 MHz, a resolution of 1600 x 1200 pixels at 60 Hz is achieved. For higher resolutions of up to 2560 x 1600 pixels at 60 Hz, the dual-link method is used. A corresponding dual-link cable with more pins is used, the video data is distributed to two TMDS transmitters and the clock rate is thus increased to 330 MHz.

Like other cables, DVI has a maximum cable length. This depends, on the one hand, on the attenuation and crosstalk of the connecting cable and, on the other hand, on the quality of the signal amplification. A maximum cable length of 10 meters can therefore still deliver optimum results; if the cable is longer, a DVI amplifier should be used.

Types of DVI

In contrast to VGA, there is not just one defined pin assignment for DVI. Depending on the pin assignment, there are different forms of DVI. The DVI connector is divided into two areas: The analog section on the left with up to 5 pins and the digital section on the right with up to 24 pins. It is also possible to screw the DVI cable to the connector, which ensures that the cable cannot simply come loose.

This picture shows the different plug versions. These are:

• DVI-A: This connection can only output/transmit analog signals and has 12 + 5 contacts. As a rule, DVI-A is only used as an adapter cable to VGA.
• DVI-D: DVI-D cables only transmit digital signals. They have either 18 + 1 contacts (single-link) for a resolution of 1920 x 1200 pixels or 24 + 1 contacts (dual-link) for a resolution of 2560 x 1600 @ 60 Hz or 1920 x 1080 @ 144 Hz.
• DVI-I: Transmits both analog and digital signals. A single-link cable has 18 + 5 contacts and is sufficient for a resolution of 16:10, i.e. 1920 x 1200 pixels at 60 Hz. A dual-link cable has 24 + 5 contacts and has a maximum resolution of 2560 x 1600 pixels.

4K with DVI?

As mentioned at the beginning, a maximum resolution of 2560 x 1600 pixels at 60 Hz can be achieved with DVI. For higher resolutions such as 4K, the successor DisplayPort must be used.

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