VGA Resolution Identification and Windows

aaron — Sun, 20 Sep 2009 02:22:05 +0000

Have you ever wondered why some monitors/cables automatically have the correct video settings available in Windows and on occasion others do not? When was the last time you extended your VGA cable to a monitor or other output device with a 50 foot cable? Did you even think to check if all 15 pins were manufactured into the cable you just bought? Me neither … and that does not change the fact that it matters.

The “optional” Sense pin, pin 9, is used by the graphics card to send +5V DC to the connected device, which plays a significant part in allowing the computer to determine resolution capabilities. This pin is crucial to monitor identification features of the VGA DDC2 standard – it is likely that without this power to the monitor, the graphics card / computer has no idea what type of monitor is plugged in…

According to pinouts.ru, the VGA DDC2 standard uses pins 9, 12 and 15 to communicate the capable screen resolutions of the device connected. So, if pin 9 is missing, then you will get a standard set of resolutions in your Windows display settings.

I recently purchased a 50 foot premium VGA cable, similar to this one on Cables to Go. Notice in the photograph of the cable end that pin 9 is missing.

Cables to Go – 50′ VGA

Next time you are running a long video cable to a projector, plasma, LCD, et cetera, you might want to spend a few “less” dollars and purchase a cable that has all 15 pins:

Sewell Direct – 50′ VGA

I hope you find this BEFORE you waste an hour trying to figure out why you can’t use the native resolution of your LCD or Plasma…

Aaron Gilbert

devtrends.com » Pin 9

VGA Resolution Identification and Windows