VGA over Cat5 ethernet cable

The diagram above shows two adapters. The one on the left converts from HD15 (VGA) to RJ45 (an ethernet socket). The one on the right converts back again. All connectors are shown from the solder side. This diagram assumes your Cat5 cable is crimped in the standard way (not as a cross-over cable). This is nifty because Cat5 is cheaper than a VGA cable (whether you're buying pre-made Ethernet cables or crimping your own off a roll), you can run Cat5 easily through conduits, electricians understand what Cat5 is and how they should run it, compared to other VGA-over-something solutions, it's cheap, compact, and does not require its own power Standard VGA extension cables come in lengths of 1.8 metres (6 feet), and if you need to go a bit further you can daisy-chain several of these, with a little signal loss. You can also get a super-special low-loss 30 metre (100 foot) VGA extension cable, but they're very expensive and very hard to find. Additionally, their fat VGA plug ends won't run through conduit smaller than about 50mm. I've run VGA over Cat5 for distances of about 15 metres (50 feet). At this range, the 800x600 screen looked fine when it was displaying a coloured background; although when it was displaying black, a lighter gray region was visible, probably due to interference from the synch signals. Your mileage will vary depending on screen res and refresh rate (lower will go further), contrast and brightness in the image (high contrast and brightness will go further), and interference from other sources (running the cable in its own metal conduit is best; if you're not in conduit, running parallel to other cables is bad).

Above is artwork for two adapters, on single-sided PCB. On the right is a male HD15 to RJ45, to plug into the back of your computer. There are three "components" on the board: the HD15 connector, the RJ45 connector, and a wire link. For the monitor end, you can use the board on the left, an RJ45 to female HD15. Or you can simply use two of the male HD15-to-RJ45, plus a female-female VGA gender changer. Print at 300 dpi. The artwork is shown here from the component side -- print it onto transparency film, and then flip the transparency over so that the text runs the correct way. There are nice wide tracks with wide gaps between to allow easy etching; and nice big solder pads to allow easy drilling and soldering. The very thin "solder pads" are merely drill guides. Index