Most TFT monitors use what is known as a digital video interface (DVI) to connect to your PC. Understanding what DVI is and how it differs from the video graphics array (VGA) interface used by old-fashioned CRT monitors is important if you're going to get the best out of your shiny new TFT monitor.

The main difference between TFT and CRT monitors is that TFT monitors are digital devices, whereas CRT monitors (and televisions) are analogue. It's just like the difference between old vinyl records (analogue) and modern audio CDs (digital).

The socket at the back of an ordinary CRT monitor that you use to connect the unit to a PC is called a VGA connector.At the back of your PC you'll find a corresponding VGA connector that is built onto the graphics card installed inside your PC. You can then use a standard VGA cable to plug the monitor straight into your PC.That's straightforward enough; all you need to remember is that the VGA interface can only handle an analogue signal.

There's a problem here, though. The graphics card inside your PC is a digital device, and the images it generates are digital.To display an image on an analogue CRT monitor the graphics card first has to convert its digital signal to analogue so it that can then be transmitted along the VGA cable to the CRT monitor.There's a risk of losing image quality during this conversion process, although this isn't really a problem for most modern CRT monitors, and they generally do produce excellent image quality.In fact, until relatively recently, many professional designers and photographers still preferred to use CRT monitors as they had a slight edge for high-quality photography or graphics work.

That is no longer the case, though, and the latest TFT monitors provide superb image quality. But, to get the best image quality that the monitor is capable of, you will need to use a DVI interface rather than VGA.As the name implies, the DVI sends a pure digital signal straight from the PC to the monitor with no conversion process to affect the quality of the image displayed on the screen.

You will, however, need to have a DVI connector on both the TFT monitor and on the PC's graphics card, along with a DVI cable to connect the two.It's easy to see if there's a DVI connector on your monitor or at the back of your PC, as it looks completely different to a VGA connector.