Messages in this thread | | | Date | Sat, 13 Apr 2002 17:46:34 -0600 | From | Richard Gooch <> | Subject | Re: linux as a minicomputer ? |
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J. A. Magallon writes: > > On 2002.04.13 Richard Gooch wrote: > >H. Peter Anvin writes: > >> Richard Gooch wrote: > >> > > >> > Actually, there is some impedance matching. I've seen monitors with > >> > hi/lo impedance switches. And I've used 15 m long high-quality VGA > >> > cables. The result has been pretty good. > >> > > >> > >> The best I've seen is to use Sun D-sub coax or plain coax inputs on > >> the monitors that have them. Those are impedance matched and can be > >> extended without problem. > > > >Sure, coax inputs are the best. But there are still problems. Even > >expensive coax has higher attenuation at higher frequencies, so the > >longer the cable, the more fuzziness you get. Also, there are > >differential delay effects between the R, G and B components. You > >don't want the pixel components to arrive at different times. So > >there's a length limitation there as well. > > > >But even though coax is better, VGA isn't that bad. 15 m gets you > >quite a lot of terminals in a web kiosk (or undergrad computer lab). > > > >BTW: I agree that X terminals suck. Even worse are SunRays. Ug! > > > > We have built a 'pseudo-CAVE' for presentations, and have six vgas > feeding sony projectors with cabling between 15 and 20m, running > at 1024x768@32. Quality is ok. > > The problem is finding good PCI vga cards, even finding any, > good or bad. Now they are TNT-M64. I'm also aware that SiS has some, > but nothing special. But, to use it as terminals, they could be ok. > > And coax is not so good. Even with expensive cable, the bounces of > the signal made me see double like drunk. Video did not worked right > until we got _golden_ connectors and soldered with silver. Believe > me you could even put more mony on the cables that on the box.
Are you sure your monitors had properly matched terminators?
Regards,
Richard.... Permanent: rgooch@atnf.csiro.au Current: rgooch@ras.ucalgary.ca - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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