Help me with VGA cabling?

April 23, 2009 7:47 AM

I want to plug a VGA cable into the wall and have the LCD TV on the other end of the room display the information. How do I do this?

Not a lot to explain, other than it is for a conference room. We are thinking about putting two LCD TVs on one wall (for presentations) and would like to plug in a laptop into another wall and have the output go to both TVs simultaneously.

I know nothing about these things, but I have a feeling are important to consider:
1) Distance from wall-jack to TVs is 40-50ft. Do I need special cabling to keep from losing too much signal over that distance?
2)Presenting computer only has VGA output, but I'm willing to consider wiring for DVI at the same time if everyone feels it's necessary.
3)The signal needs to split at some point so that it can run to both TVs. Anything special I need to accomplish this?
4)I've seen VGA wall-mounts on the internet, but I don't know what the back looks like. Do I just basically plug a VGA extension cable into the back and run it through the wall?

Thanks for everyone's help. This probably shouldn't be a terribly difficult project, but looks daunting to someone unfamiliar with the requirements.

posted by wabashbdw to technology (4 comments total)

Have you considered a VGA-to-cat5 adapter? (I haven't used that one precisely but can't find the model I had in hands). For 1024x768, it worked like a charm, and we were plugged through a networked conference buidling (= way more than 40ft of cat5 cable between the two walls).
posted by ddaavviidd at 7:51 AM on April 23

you'll also need a VGA signal splitter
posted by jrishel at 8:25 AM on April 23

You could try a VGA balun. Here is one that's a wall mount that I just installed (link). Here's a DVI. Allow me to share my experience: I had one 42 LCD wall mounted with a PC (VGA) input. Behind it was the Niles wall outlet. A Cat5 ran inwall and around a corner to a desk, about 30 ft. At the desk was another Niles wall outlet (you need two baluns). For each outlet there was VGA cable - one to LCD and the other to laptop.

When I first ran it, everything looked great until I turned it on. The picture would flicker and pop in/out. There was strange banding in the image also when I was able to get it steady. Ultimately proved unsuccessful. After lots of problem solving, I ultimately went to remove the in-wall Cat5 between the baluns and pulled a new Cat5, this time to be sure it was fully shielded with shielded jacks (the old was just extra cable I had lying around that worked before on test but not after being pulled in-wall).

After replacing the cable, it worked, though it wasn't straightforward. The best resolution sent from laptop through the baluns to LCD is 1024x768 @ 60Hz. Trying to send a 1280x768 image to take advantage of some extra width caused the image to creep off the screen for an unknown reason (maybe something to do with overscan?). You're trying to split the image to two screens, I don't know if that would work, but some kind of boost to the signal outside of the baluns may be needed, given the loss along the line. I only had a single screen.
posted by spoons at 9:22 AM on April 23

spoons, that's a passive balun. Active baluns at both ends work much better for UTP or STP. For this I'd just stay native, though, because it's easy.

Answers in order:
1. Maybe not if you're only doing 1024x768@60Hz, but I'd buy the 50ft cable, a 20ft cable and passive splitter for the branch at the first TV and test those first. If they work well, then stop right there. If you have signal problems, buy a signal splitter/amplifier (see below).
2. Not for resolutions under 1280x1024. People are all over digital but analog works great, and it's cheap, and whatever.
3. Signal splitter here for $16. I'd go from the wall plate to the splitter, which then branches to both TVs.
4. They're (female to female) HD15 couplers. Here's one for $3. Typically you saw a hole in your drywall and put in a low-voltage "old work box" and attach the plate to that, run a cable in the drywall and come out to either another coupler plate or just a plate with a grommeted hole (or if you're REALLY strapped for budget or you just don't care - just the hole!), for a permanent connection to a mounted TV.

You might get lucky and it'll work without any active circuitry. I've had a lot better luck with TVs accepting weak signals than projectors, but your mileage may vary.
posted by ostranenie at 1:19 PM on April 23