Question : Problem: How does a monitor know to go to sleep?

Hi,

Just an interesting question that I cannot find an answer too and it is bugging me.

When I put my computer to stand-by mode, my monitors automatically go into sleep mode and the green power lights go orange.

likewise when I set the power options in the control panel.

How does the monitor know that it needs to go to sleep. Example,

Do monitors have a processing chip or something to accept and react to commands.
Does the computer send a software command and the monitor receive it?
Does the video card cut the power output and the monitor knows this and reacts accordingly.
ETC....

This is different that just pulling the video cable, as that causes a "check cable" on the monitor, as opposed to a "entering sleep mode" message.

I would love to get an answer as I haven't got any sleep for days trying to understand....... LOL

thanks

Booster

Answer : Problem: How does a monitor know to go to sleep?

Here is some info on the 15 pin highdesnsity cables,



VGA (VESA DDC)
VGA=Video Graphics Adapter or Video Graphics Array.
VESA=Video Electronics Standards Association.
DDC=Display Data Channel.

Videotype: Analogue.

(At the videocard)
(At the monitor cable)

15 PIN HIGHDENSITY D-SUB FEMALE at the videocard.
15 PIN HIGHDENSITY D-SUB MALE at the monitor cable.

Pin Name Dir Description
1 RED Red Video (75 ohm, 0.7 V p-p)
2 GREEN Green Video (75 ohm, 0.7 V p-p)
3 BLUE Blue Video (75 ohm, 0.7 V p-p)
4 RES - Reserved
5 GND Ground
6 RGND Red Ground
7 GGND Green Ground
8 BGND Blue Ground
9 +5V +5 VDC
10 SGND Sync Ground
11 ID0 Monitor ID Bit 0 (optional)
12 SDA DDC Serial Data Line
13 HSYNC or CSYNC Horizontal Sync (or Composite Sync)
14 VSYNC Vertical Sync
15 SCL DDC Data Clock Line

Note: Direction is Computer relative Monitor.
Contributor: Joakim Ögren
Source: IEEE
Please send any comments to Joakim Ögren.