Understanding the new DisplayPort video-connection standard

A few years ago, the VESA consortium who manage standards concerning video display equipment have released the DisplayPort video connection standard to connect a computer or similar device to a display. This has yielded increased improvement over the legacy VGA, DVI and HDMI standards that are currently in use for this purpose.

At the moment, it has been mainly deployed by Apple in their recent-issue Macintosh computers and monitors and I have known that the iMac all-in-one computers have the ability to work as a DisplayPort monitor. Now, other manufacturers are releasing laptop and desktop computers as well as aftermarket graphics cards equipped with this connection in to their model lineups. This is also being augmented with a trickle of monitors and “business” projectors that come with this connection and this trickle will turn in to a flood as this connector comes down the model lineups.

Improvements

Small-size connector

There is a standard connector that is similar to a USB plug for applications where space doesn’t matter like display cards or most regular monitor and projector designs. This connector also has a “latching” design that allows for high-reliability connections in applications where this is desired.

Then there was a “MiniDisplayPort” connector that is half the size of this connector and is intended for applications where space is limited like laptop computers, sleek monitors and ultra-low-profile computer housings. This is actually the standard being implemented by Apple in their current-issue Macintosh platform hardware.

Single pipe

This standard, like the SCART and HDMI video-connection standards, allows for a single pipe for high-resolution video, digital audio and bi-directional communications. Some applications like multi-function monitors with integrated sound, Webcams and USB hubs; touchscreen displays and projectors with integrated cursor-control functionality will benefit from this functionality because there is only one cable needed between the host device and the display.

The latest version (1.2) of this standard also allows for multi-display setups from one connection on the host, whether as a daisy-chain or in a “hub and spoke” manner. This then allows for simplifying multi-monitor display arrangements or monitor / projector setups.

It is also worth knowing that the DisplayPort standard also allows for IP-based network connectivity between the host and the display, which could benefit those displays that have some form of network functionality.

Increased performance

High-resolution, High colour depth (digital photo and video)

Increased distance between host and display

The distance between the host device and the display has been increased to 15 metres without the need for repeaters or amplifiers. This would benefit large video-display setups where the display computer would need to be away from the display screen or projector unit, such as meeting rooms, churches, cinemas and the like.

Adaptors available for legacy displays

If you buy a DisplayPort-equipped computer or retrofit your desktop computer with a DisplayPort-equipped video card, you can still connect your computer or video card to your existing monitor. This is feasible through the availability of DisplayPort – VGA / DVI / HDMI adaptors.

Issues to be careful of

Use of DisplayPort – HDMI adaptors

If you want full proper HDMI operation such as “single-pipe audio” with a DisplayPort-HDMI adaptor, you will need to make sure that the DisplayPort host computer is capable of DP++ behaviour. This is to ensure that the proper logic is going to occur between the host device and the HDMI display setup which may include a separate HDMI “sink” device for sound like a home-theatre receiver.

DisplayPort 1.2 multi-display setups

A DisplayPort setup which is established in a daisy-chain fashion requires a DP 1.2 host at the head of the chain and DP 1.2 monitors down the chain, but a DP 1.1a monitor can be used as the last display in the chain. Alternatively, DP 1.1a monitors can be used as the “spokes” displays in a DP 1.2 setup if they are connected directly to the hub.

It is also worth knowing that the DisplayPort 1.2 multi-monitor setups support “multi-streaming” with displays showing different images from one host. This can suit most multi-display applications such as editing environments, “extra-wide desktops” or “operator screens” for projector setups where each monitor must have different video.

What to look for

If you want to make sure that your system can support the display requirements of now and the future, make sure that the display subsystem can support DisplayPort 1.2 with DP++ functionality. This can cater for multi-screen displays, the current crop of HDMI-equipped display and audio hardware amongst other things.

Whenever you buy or specify a DisplayPort monitor for a multi-screen display or as an “operator screen” for your DisplayPort projector, make sure that it supports at least DisplayPort 1.2. You can get by with a DisplayPort 1.1a monitor or projector at the end of a “daisy-chain” setup on as a “spoke” from a hub-based setup with a DisplayPort 1.2 hub.

Conclusion

Once you are aware of the caveats outlined above when buying or specifying DisplayPort hardware, you can be sure that you can benefit from the DisplayPort standard offers.

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