Do You Need DisplayPort on Your PC?

Next Generation Video Connector for Personal Computers

An example of a DisplayPort cable
Belkin

Over the years, the computer industry has seen a wide number of different video connectors. The VGA standard helped bring high resolution and color displays away from the first TV video connectors. DVI introduced us to digital displays that allowed for greater color and clarity. Finally, the HDMI interface integrated a digital video and audio signal into a single cable for use with home theater and even PC displays.

So, with all of these advancements why is there the DisplayPort connector? That's precisely what this article looks to explain.

Limitations of Existing Video Connectors

Each of the three major video connectors has problems that limit their use with future computer display. Even though they have addressed some of the issues, some still remain. Let's take a look at each of the formats and the problems that they have:

DVI

  • Single DVI limited to 1920x1200 resolution with 24-bit color
  • Dual-link DVI limited to 2560x1600 resolution with 24-bit color
  • Heavy cabling requires connector to be screwed into card/display
  • No audio support

HDMI

  • Version 2.0 supports up to 4K Resolutions but fairly uncommon still
  • Version 1.3 supports up to 2560x1600 resolution with audio stream
  • Version 1.1 supports up to 1920x1200 resolution with audio stream
  • Category 1 cables limited to 5 meters in length

DisplayPort Basics

DisplayPort was developed among the members of the Video Electronics Standards Association.

This is a group of roughly 170 companies that develops and decides standards to be used with computer displays. This is not the group that developed the HDMI standards. Because of the greater demands of computers and the IT industry, the VESA group developed DisplayPort.

In terms of physical cabling, the DisplayPort cables and connectors look very similar to the USB or HDMI cables that are used today on most computers.

The smaller connectors makes for easier cabling of the system and allows the connector to be placed on a wider range of products. Many thin notebook computers can't properly fit a single VGA or DVI connector currently, but DisplayPort's thin profile allow it to be put on them. Similarly, the narrow design allows up to four connectors to be placed on a single PCI bracket in a desktop PC.

The current signaling methods used on the DisplayPort connectors also allow for a larger amount of data bandwidth over the cable. This allows it to expand beyond the current 2560x1600 resolution limits of dual-link DVI and HDMI v1.3 connectors. This is not really an issue for existing displays, but it is important for the future growth of 4K or UltraHD Displays that require four times the data bandwidth of typicel 1080p video and the eventual move to 8K video. In addition to this video stream, the cabling can also support an 8-channel uncompressed audio stream similar to that of the HDMI connector.

One of the major advances with the DisplayPort system though is the auxiliary channel. This is an additional channel to the standard video lines in the cable that can carry additional video or data information for more demanding applications.

An example of this can be the connection of a webcam or USB port that is built into the computer display without the need for additional cabling. Some versions of HDMI have added Ethernet to them but this implementation is extremely rare.

One thing many people need to be aware of is that the ThunderBolt connectors are essentially the DisplayPort standard with exapnded side channel features. This is not true of all versions though as ThunderBolt 3 is based upon the USB 3.1 connectors and standards which makes things even more confusion. So, if your PC has ThunderBolt be sure to check the version to make sure it is compatible with your display.

DisplayPort More Than Cabling

Another important advance with the DisplayPort standard is that it moves beyond just the connector and cable between a PC and display. The technology can also be used inside the physical displays of a monitor or notebook to reduce the amount of connectors and wiring required. This is due to the DisplayPort standards including a method for direct display connections.

What this means is that the display can remove many electronics necessary to convert the video signal from the video card into one that can be used to drive the physical LCD panel. Instead, the LCD panel uses a DisplayPort drive that bypasses these electronics. Essentially, the signal that comes from the video card directly controls the physical state of the pixels on the display. This can allow for smaller displays with fewer electronics components. This can conceivable allow prices of the displays to drop.

With these features, it is hoped that the DisplayPort can be integrated into a wider range of products other than computer displays, PCs and notebooks. Smaller consumer devices could also integrated the DisplayPort connector for use with compatible monitors.

Still Backwards Compatible

While the DisplayPort standards currently don't include any backward compatible signaling within the physical cable and connectors, the standard does call for support of the older display standards including VGA, DVI and HDMI. All of this will need to be handled through external adapters. It will be a bit more complex than the traditional DVI-to-VGA style adapter but still contained within a small cable.