EDID stands for 'Extended Display Identification Data'. It is generally used to let a PC determine the abilities of a monitor, such as:

1. Whether it is an analog (CRT) or digital (flat-panel) monitor.
2. It's maximum resolution.
3. Specific resolutions available on the monitor.

4. Whether it is wide-screen or not.
5. The manufacturer name.
6. HDMI compatibility.
7. Audio abilities.
8. Color-space abilities
... etc.

EDID data is requested by the source (PC, DVD, etc.) over a 'DDC' link (2 specific pins on a HD15 or DVI connector) usually on power-up or when a monitor is attached. EDID on an analog monitor is not usually required in order to make it work properly (ie. the PC will assume that it can receive certain standard reoslutions). EDID on a digital monitor is an absolute must, or the PC/DVD player will not output anything.

Under some circumstances, a PC will not auto-detect a new monitor being attached and you will have to re-boot the computer. This usually depends on the make or model of a graphic card.

Also see EDID manager in CORIO2 units