I'm currently researching hardware components for some kind of information terminal we're building.

This application of ours makes use of three output screens:

(1) A touch screen where all user input is made;

(2) A regular LCD monitor where the requested information is being displayed; and

(3) A projector which displays exactly the same signal as screen (2) does.

(All screens will run at the same resolution of 1024x768 btw.)

Now I figured that using a dual-head video card would be sufficient, let's say a Matrox P690 low-profile PCI card. This would involve having a Y cable connected to the graphics card itself, then two DVI-to-VGA adapters at each end of the Y cable, and then having a VGA splitter on one of the VGA outputs.

The following shows the setup in question:

0--1---------2-> VGA (DSUB-15)
      ----2-3---------> VGA (DSUB-15)
               -----------------> VGA (DSUB-15)

0: graphics card (LFH60 jack)
1: LFH60 to DVI-I dual monitor Y cable
2: DVI-to-VGA adapters
3: VGA splitter cable


Will this work? I'm particularly concerned about the following points:

  • Can a low-profile PCI video card output a signal which is strong enough for three monitors (even if it's a dual-head card)?

  • Does the combination of so many adapters and splitter cables work? (The LFH-to-DVI cable comes with the video card)

  • Will the VGA splitter cable degrade the signal on the output screen & projector significantly? (If so, would a USB-powered splitter cable remedy this problem?)

I can't possibly expect anyone to answer all those questions, but any input is appreciated.


I don't think the signal strenght will be an issue, but using a DVI-splitter cable might give you better looking image, but they are known to have some issues (cheap ones atleast). I don't think there should be any problems as long as you don't try to run 1920x1200 resolution (your 1024x768 will work nicely) through that setup and use reasonably high quality cables.

Actually, at 1024x768 you probably wont see any quality improvement even if the signal was kept DVI all the way.

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