DVI Explained

We often get asked about DVI cables and adapters, so without going into too much detail we shall cover the basics. There are 3 types of DVI..

• DVI-A – This is the analogue version that DOES NOT handle digital signals
• DVI-I – This can handle both digital and analogue signals
• DVI-D – This is the digital version and CANNOT handle analogue signals

DVI-I and DVI-D can then be split down in to single link and dual link, the main difference between the two is dual link offers larger screen resolutions.

The reason for DVI-A is to allow VGA monitors/equipment to be connected to a DVI port, this is done by connecting the 15 pins used in the VGA connector.

The reason for DVI-I is to allow the choice of using either a VGA or a DVI-D monitor/equipment, this is done by connecting the VGA pins and adding extra pins to make DVI-D dual link.

The reason for DVI-D is to allow digital monitors/equipment to be connected in either single link or dual link modes that only have digital signal capability. As it is digital you can get cables and adapters that are compatible with HDMI although only DVI-D single link resolutions can be achieved.

The following diagram shows the difference, DVI-D has a single thin flat pin/socket.

That is the basic version of DVI explained and most people won’t need to know any further. Now the ports are covered lets move on to cables…

As explained above, if you have a DVI-A or DVI-I port you can use a DVI-A cable to connect VGA equipment.

It gets a little more complicated with DVI-D as as you can use  either DVI-I or DVI-D cables in single link or dual link configuration, this just depends on the resolution you want.

My personal view is if you don’t know what you want then pick the middle guy, DVI-I as it will work with both VGA and DVI digital signals.

As well as all that has been mentioned above you can actually buy converters that will convert the analogue signals into digital and vice versa. This can only be done with a chipset. You will see a lot of VGA to DVI and vice versa cables and adapters on the market without chipsets and these simply will not work.

The best advice we can offer is as follows…

• Decide what equipment you want to connect together.
• Read your equipment manuals to see what port types you have.
• Decide what resolution you want.
• Work out if you just need just cables or both cables and adapters.

Failing that, give us a call with as much information as you can get on the above points and we will advise you from there.