Gefen DVI DL: Dual Link DVI + USB KVM
by Anand Lal Shimpi on October 19, 2005 12:05 AM EST- Posted in
- GPUs
Introducing the Gefen DVI DL
Fairly well-known in the home theater community for their HDMI switch boxes, Gefen was the logical choice for finding a dual link DVI KVM. The benefit of a DVI based KVM is that a lot of the issues that plagued old analog VGA KVMs are no longer a problem, thanks to the fact that DVI-I signals are transmitted in the digital domain, meaning that the signal that leaves your computer is exactly what gets displayed on your monitor. With analog VGA based KVMs, you often had image quality degradation at higher resolutions, especially if you happened to have a lower quality KVM. So, in theory, thanks to an all-digital connection, we should have no problems with just about any DVI based KVM switch. Our confidence in the DVI specification aside, we had heard very good things about Gefen, once again from the home theater community - and if anyone has a very critical eye when it comes to image quality, it is the home theater community.
Priced at $399, the Gefen DVI DL is not cheap, but neither is the monitor you'd be hooking this up to, so although we don't agree with the price premium, this product isn't exactly targeted at the low end of the market. So, after you're done buying your $600 video card and $2500 monitor, what's another $400 for the DVI DL?
The Gefen DVI DL is a fairly simple device that acts as an electrical switcher between two computers. The DVI DL will switch between two dual link DVI inputs, analog audio as well as USB 2.0. It is important to note that the DVI DL does not provide USB or DVI "emulation"; in other words, when you switch between systems, it is akin to unplugging the USB and DVI cables from one system and plugging them into the other - that's exactly what the OS "sees" when you switch using the DVI DL. Some units do provide USB emulation, but we'll address this topic later on as we talk about our experiences with the DVI DL.
The only somewhat confusing aspect of the setup deals with USB setup. The two type A ports are labeled USB Out, and this is where you plug in the USB devices that you wish to switch between computers (e.g. keyboard, mouse, etc.). You can even plug in a USB hub to these ports if you'd like (more on that later). The two type B ports are for connecting to your computers: In 1 goes to the first computer and In 2 goes to the second. Obviously, it's very important that DVI 1, In 1 and Audio 1 all go to the first computer, and all of the ports marked "2" connect to the second computer. Otherwise, you'll only be switching some of the components to the right system when you go to hit the select button.
Fairly well-known in the home theater community for their HDMI switch boxes, Gefen was the logical choice for finding a dual link DVI KVM. The benefit of a DVI based KVM is that a lot of the issues that plagued old analog VGA KVMs are no longer a problem, thanks to the fact that DVI-I signals are transmitted in the digital domain, meaning that the signal that leaves your computer is exactly what gets displayed on your monitor. With analog VGA based KVMs, you often had image quality degradation at higher resolutions, especially if you happened to have a lower quality KVM. So, in theory, thanks to an all-digital connection, we should have no problems with just about any DVI based KVM switch. Our confidence in the DVI specification aside, we had heard very good things about Gefen, once again from the home theater community - and if anyone has a very critical eye when it comes to image quality, it is the home theater community.
Priced at $399, the Gefen DVI DL is not cheap, but neither is the monitor you'd be hooking this up to, so although we don't agree with the price premium, this product isn't exactly targeted at the low end of the market. So, after you're done buying your $600 video card and $2500 monitor, what's another $400 for the DVI DL?
The Gefen DVI DL is a fairly simple device that acts as an electrical switcher between two computers. The DVI DL will switch between two dual link DVI inputs, analog audio as well as USB 2.0. It is important to note that the DVI DL does not provide USB or DVI "emulation"; in other words, when you switch between systems, it is akin to unplugging the USB and DVI cables from one system and plugging them into the other - that's exactly what the OS "sees" when you switch using the DVI DL. Some units do provide USB emulation, but we'll address this topic later on as we talk about our experiences with the DVI DL.
The only somewhat confusing aspect of the setup deals with USB setup. The two type A ports are labeled USB Out, and this is where you plug in the USB devices that you wish to switch between computers (e.g. keyboard, mouse, etc.). You can even plug in a USB hub to these ports if you'd like (more on that later). The two type B ports are for connecting to your computers: In 1 goes to the first computer and In 2 goes to the second. Obviously, it's very important that DVI 1, In 1 and Audio 1 all go to the first computer, and all of the ports marked "2" connect to the second computer. Otherwise, you'll only be switching some of the components to the right system when you go to hit the select button.
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johnsonx - Wednesday, October 19, 2005 - link
er... that was supposed to be loses and lose, not looses and loose...but you probably got the idea just the same.
bupkus - Wednesday, October 19, 2005 - link
With an eye for the future, I envision an uber-large LCD I can use for movies, computer games and general computer use. Forget the KVM; I see a single or multiple windows for each computer be it M$ Windows or linux or whatever. I see minimizing all windows, and then maximizing my UT2004 window, or DVD, etc.This is like the X-window systems I recall from college. Now, I'm no expert on X-windows, nor do I expect it could do the job as it is today, but, hey, it'm my freakin fantasy, not yours.
bupkus - Wednesday, October 19, 2005 - link
"it'm"? Man, how did I miss that key so badly? "m" is nowhere near "s". Twitchin' fingers.OrSin - Wednesday, October 19, 2005 - link
Why spend $400+ on switcher. Just by a 20in display for second system for under 400.Yeah its not the great 30in display but who needs 30in for both systems?
Also how can you sell a 400 switch that just don't work.
IronChefMoto - Wednesday, October 19, 2005 - link
Skimming through this article, it makes me shake my head. It's hard to find decent DVI KVMs. The Belkin SOHOs are twitchy at best, and the only other name brand I've been referred to (and actually away from) is IOGEAR.Right now, I use a 4-port VGA/USB KVM for a Shuttle XPC, PC laptop, and whatever 3rd project machine I'm using. After a recent job change that required a switch to a dual DVI monitor Mac, I'm hating having to try and find a decent DVI KVM replacement.
I need a dual monitor DVI KVM if I'm to (a) get a 2nd 17" monitor at home to mimic my work setup and (b) replace my PC laptop with a Mac. I've priced out the dual VGA and single DVI offerings from Belkin's SOHO line, and they're expensive. The dual DVI models from IOGEAR are 30-50% more expensive than those.
For the time being, I'll stick with my single VGA 4-port Belkin SOHO which works fine, after some wrangling. I can't afford a second non-DVI Samsung flat panel anyway, and the Mac laptop is even farther off.
Bottom line -- if you start needing 2 computers, 2 monitors, etc. -- KVMs are gonna get expensive. And that's assuming they don't have bugs like this Gefen did, or like the ones I've read about for IOGEAR products.
IronChefMorimoto
BoBOh - Thursday, October 20, 2005 - link
At work, I have a DVI (not DL) kvm from a company called "Adder". It's flaky with the tilt-wheel mice, but other than that has been flawless. Give 'em a shot.Patman2099 - Wednesday, October 19, 2005 - link
I dont know if macs have similar driver issues, but as far as the DVI detective issue goes, try changing the driver to a pre 5.8 catalyst driver.ive had some screwy issues with DVI on my HTPC since catalyst 5.8 , including things going to hell whenever the htpc loses its connection with the TV(being turned off, changing inputs, etc) before 5.8, everything worked flawlessly and i never had any issues.
Chuckles - Wednesday, October 19, 2005 - link
Anand,I run a slightly smaller scale KVM system between my Mac and PC (12x10 monitor, GeForce 2 MX (Mac), 9600 (PC), Belkin 2-port SOHO DVI KVM). The setup definitely has its quirks and flaws. F13, F15, and the Volume controls on my Apple keyboard no longer register, and about 1/4 of the time, the mouse gets forgotten by the PC.
With regard to the monitor issue, what happens when you hot-plug the monitor into the G5 (without the KVM)?
Also, did you have any peculiarities or restrictions with the keyboard operation when using the KVM?
Lonyo - Wednesday, October 19, 2005 - link
It's not a $600 video card + $2500 monitor + $400 KVM, it's TWO $600 video cards, a $3000 monitor (apparently) and a $400 + $160 KVM, but still as a part of the whole cost, $560 isn't much when you're spending $4000+ anyway.lopri - Wednesday, October 19, 2005 - link
Where can you get a 30" Cinema Display for that price? After adding tax I get a $3,240 quote. Misinformation is as bad as misjudgiment. :~P
Also can you possibly tell me why, oh why, don't other manufacturer's make 30" monitors w/ 25x16 resolution? This has been bugging me so bad. I'd love to have a 30" monitor but I do not want to give a dime to such a greedy company. If Apple can sell 30"s, surely Samsung, LG, Dell, et al. can. Apple is not making the panels on their own anyway. (I believe it's Samsung)
"Market demand" seems to me a weak excuse because these companies make even more expensive (read: $7,000 and up) LCD/Plasma screens. And strangely they are all 1280x768 (or something like that) resolutions. (OK, there are 1900x1080s too, but still way too short of 2500x1600)
Do you have any inside knowledge of this situation? This question's been bugging me for years. (since the 30" CD came out) I'd also like to know if there is any hope to get a bigger res from other manufacturers than Apple in the near future.
Thanks alot.
lop