Cable Lengths and You - Physically Moving CPUs Away

I don't know about other people, but I decided to locate my equipment a little further away than RIGHT NEXT TO ME. (10 computers is not only LOUD but it is quite hot too). The shortest cable length is DVI. It has a spec of 15 ft away for dual link DVI. With VERY well shielded 24 AWG or larger (22,20,etc) cables, you can push it to 25-30ish ft but not much more before it snows out and is completely unusable.

Fortunately, there are products designed to extend Dual Link DVI (needed for my 30" monitors).

Genfen makes a box for about $250 (MSRP) - but I bought mine for $170 or so - that extends up to 200 ft. You need 1 per DVI cable. (Generally 1 per monitor).

http://www.gefen.com/images/dvidlboostertop.jpg

http://www.gefen.com/kvm/product.jsp?prod_id=2938

Don't be fooled by the size in the picture. These units are MAYBE 2" by 2". Both the detective and the DL Extender are the same size.

You can daisy chain them further if you would like and there are even DVI to ethernet/fiber options out there too - for REALLY long cable runs.

USB is the next hardest. USB 2.0 spec calls for around 15-20 ft at the maximum. You can push it to around 25 but you start to get random cutouts where the signal gets lost then reacquired. Not good when you are in combat. Sometimes you even have to disconnect and reconnect the cable - also not good. Fortunately, USB is easy to extend. Either put a hub on the end of a 10 - 15 ft cable, or buy USB extenders. Both function the same way, refreshing the signal. You can daisy chain these for quite some distance - at least 4 or 5 hops for sure - so around 50 - 75 feet at least. Of course, there is USB over eth/fiber too I am sure but those are never cheap.

Also of note - you can only have 4 hubs. Any more than that does not work. No, really. USB extenders act as hubs. A lot of card readers, etc also act as hubs - so check your control panel.

http://i183.photobucket.com/albums/x...oW/MaxHubs.jpg

Monoprice sells some cheap USB extenders and hubs. Just keep it to 4 or less per machine.

PS/2 can be sent over at least 50 feet without any problems. The bandwidth and frequency is so low that standard cable shielding is plenty for this signal.

VGA can generally be sent up to 50 feet without any problems - just be sure to use shielded cables.

Ethernet of course can be sent hundreds of feet. HDMI can be sent at least 50 feet - easily more as it is a twisted pair design at its heart - but it cannot (yet?) send Dual Link level resolutions, plus is not commonly available on video cards.

Audio can be sent quite a ways but if you are going to hit 30+ ft then you should consider either toslink optical or coax digital SP/DIF. Those are good for significantly long runs - the coax is very well insulated and even though the optical signal is not high quality - it will stay digital the entire length and should be fine for standard, reasonable runs with less popping and random noise. Keep in mind though that you can still degrade digital signals - but it would take a significant amount of noise and a significantly damaged cable or a really poor source to ever notice this in a sub 200 ft run with decent cables.

If you are using any kind of DVI splitter and are encountering problems where your display is not being detected (because it is now "disconnected" - aka switched) then Gefen has a neat little device that transmits the EDID data to the video card, tricking it into thinking the monitor is still connected.

This means you can turn on a computer with the switch in the opposite position and the OS will not disable the monitor, thinking its not there.

http://www.gefen.com/kvm/product.jsp?prod_id=1378

About $70 each retail.

You need 1 per port you are going to connect.

Gefen makes some DVI switches but they are VERY expensive and pure digital. Go manual and save a ton of money. You lose the ability to remote switch though, unless you extend the wires enough and use a DVI booster or hook up a custom switch yourself.