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I’m Wired – Part 1

10/01/14 by EE Team

This is a new series on Audio Visual equipment that is commonly used on a trade show floor. The biggest thing to get right is the type of connections and their compatibility. There are many different types of connections so it is good to know what they are and what they can and cannot do. So let’s go over the names of the connections or ports and then we will take each one in some detail. In this series we will discuss VGA, HDMI, DVI, and the newest kid on the block – the Display Port.

First there is VGA. VGA stands for Video Graphic Array. VGA, the original PC connection, was developed by IBM back in 1987. It started with a display resolution of 640 x 480 which is a very low resolution by today’s standard. VGA was followed by super VGA which gives you a higher resolution like 1024 x 768. All VGA connections transmit an analog signal. So what is an analog signal? Without getting in too much detail an analog signal can be defined as a continuous electrical signal. The video card in a computer converts the computers digital information into an analog format then transmits it though a VGA cable to the monitor.

So why are there 15 pins in a VGA connection? The short answer is with the separation of the signals a computer monitor can have many more pixels then a regular TV set. Pixels are the individual dots on a monitor screen that create the picture. For example: if a monitor can support an 800 x 600 picture format that means it can display up to 800 pixels across and 600 pixels vertically. The more pixels you have the better the picture. So what are all the 15 pins in a VGA connection?  Ok let’s have some fun and name them all:

1. Red Out

2. Green out

3. Blue out

4. It is unused. It doesn’t do anything

5. Ground

6. Red return ground

7. Green return ground

8. You guessed it – Blue return ground

9. Another unused pin.

10. Sync return ground.

11. Monitor ID “0” in

12. Monitor ID 1 in or data from the display

13. Horizontal Sync out

14. Vertical Sync

15. Monitor ID 3 in or the data clock.

So then you could ask why don’t they make it only a 13 pin connection. Actually, I have no idea. My guess is they wanted to leave some room for future technology. If you know the answer, write back to me in the comment section below the video.

If you look at most VGA cables there is one pin missing on purpose. So why not two pins missing? My guess there is for superstitious reasons – you know unlucky number 13.

In a regular television all of these pins would be combined into a single composite video signal. You know it is the gold video pin that goes with the red and white audio pins and the quality of the picture would just not be as good.

As always, please respond with your questions or comments and let others know about EXHIBITOR LOUNGE.COM. We will see you next week. Until then, I am your host Michael Gray telling you to RELAX in the Exhibitor Lounge.