Digital or Analog?

I said at the beginning of the last section that flat-panel monitors are digital devices. That's true, but many LCD monitors have analog VGA (Video Graphics Array) inputs, either as a companion to the digital input or as their only input connector. The analog connection allows users with older computers and graphics controllers to replace old CRT monitors without the need to open up the computer case and swap video cards. Because the only outputs on those older controllers are analog, the signal to the monitor's analog input passes through an analog-to-digital converter. If you're thinking that it's inefficient to convert from digital to analog in the controller and from analog back to digital inside the monitor, you're absolutely right, but it has allowed the monitor manufacturers to sell lots more flat panels.

CRT monitors are always analog. If you're shopping for a new LCD monitor, your best choice is one that has a digital input connector, even if your existing computer's graphics card is analog only. If you plan to use the new monitor with an older computer, the best way to take full advantage of the monitor's performance is to buy and install a new graphics card with a digital output at the same time. But if you can't replace the computer's existing video card, look for a monitor with both analog and digital input connectors.