Gefen DVI DL: Dual Link DVI + USB KVM

by Anand Lal Shimpi on 10/19/2005 12:05 AM EST


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  • Tutor - Sunday, October 30, 2005 - link

    Dr. Bott has great KVMs. I use a VGA with USB switcher and it is great. Did not have the opportunity to test their DVI product, but maybe Anand will ;-)
    It is not dual link, but rated for 1920 * 1200. German web site states a dual link device will be available in the future.">
  • kencl - Monday, October 24, 2005 - link

    Just thought I'd pass along">another software solution. It's M$ Windows only unfortunately, but that may be exactly what some of you are needing (not me, unfortunately, I need to switch into a Linux system - maybe there's an Win32 X-Windows client out there somewhere....) Reply
  • supaxi - Saturday, October 22, 2005 - link

    I know this is a bit out of left field, but I wanted to mention a software KVM program that I use a lot. It lets you use one mouse and keyboard with any number of systems. I use three computers at work and this is real life saver as I hate KVM switches. You can try it at">

    They don't support unix but I'm sure you could find a similar program out there someplace.
  • tortoisehead - Thursday, October 20, 2005 - link

    I bought a gefen switcher a few weeks ago because remote logins don't cut it for video or gaming, and I was sick of switching the usb and dvi cables between my pc and mac. I have the "2x1 DVI KVM" and have had several issues like the ones the reviewers came across. In case there are other gefen owners reading this article, here's some info on how I got my setup to be stable.

    I went through hell just trying to to get the ability to switch back and forth between my PC and Mac without praying that it would work correctly. You wouldn't think a switcher would be that hard, but like others have said no one can seem to get it right. I had crashes, devices not being recognized correctly, and the monitor not turning on when I switched. Sometimes repeatable, sometimes not. That can be so frustrating.

    In the end I replaced the DVI cable going to my Mac with one I got from work (from Dell). That ended the dock crashing every time I switched back to my Mac. Who knows what is wrong with the cable that gefen gave me. I asked in their forums, and they recommended to pull out one of the DVI pins! Too bad after I did that the cable didn't work at all anymore.

    As far as the PC, I had two wireless logitech controllers that were apparently causing issues with the switcher and XP. One for the keyboard, and one for the mouse. Once I set it up to communicate with both devices using the keyboard controller, I removed the mouse-only controller and had no more usb problems.

    One of the most frustrating things I ran into was the same thing documented in the review. You bring up any problems in the gefen forum and the first thing they tell you is to buy their $80 "DVI Detective" to fix their own buggy hardware! That's just lame, especially with the price of DVI switchers. And if Macs have problems with DVI cables having certain pins, why not have the option of one of your DVI cables being a "Mac" version when you buy the switcher?

    So long story short, I can't really recommend gefen's products either. Please chime in if you have had a great experience with an affordable DVI switcher!
  • Scorpion - Thursday, October 20, 2005 - link

    Wow I'm so happy to see a KVM article! I still use my old Hawking 4-Port KVM. I've been trying to upgrade to a newer KVM with DVI and USB support for mouse and keyboard, but I just can't find any! I was even at a Fry's (out of town, there isn't one where I live) and I looked at this huge Isle of KVMs, and I could maybe find ONE that supported DVI or USB, but never both, and the ones I found just didn't have the functional look I wanted. Where is this market? I know several people with multiple computers and limited desktop real-estate for multiple monitors, keyboards, and mice. KVMs are great for this situation, there just aren't enough people who do it right.

    I'm really looking for a good KVM DVI+USB, not to be used with any wireless keyboard or mouse. If anyone has any recommendations I'd greatly appreciate it. It's good to see some attention pointed towards this market segment.
  • Nocturnal - Wednesday, October 19, 2005 - link

    I wonder if more sites did more reviews on KVMs that they'd kinda get to work on fixes for the flaws that the reviewers find. I want the IOGear GCS1774 but it does not work with any nVidia 3/4 chipset which is very bad. Reply
  • ky - Wednesday, October 19, 2005 - link

    How do you get a 30" for $2500?

    Pixar and Apple employees get a standard discount of 15% before tax so that comes pretty close to $2500 ($2549). Maybe reviewers get > 15% off? Or another reason might be due to cash back discounts or site referrals (fatwallet) you might bring it closer to $2500.

    Why buy a $400 switcher when a 2nd 20" display is only $400?

    I dunno about you but if both my computers can power the 30" in all its magnificence, I'd rather use the 2nd computer w/ the 30" than a piddly 20". OTOH, w/ a 2nd monitor, you can use both at the same time rather than alternatively. It's just a preference thing, I guess.

    Gefen has has a long history of "screwing" their customers with their suggestions (read: upselling) of buying additional products to solve problems with products you've already purchased. Back when I was using the 23" display, they suggested I buy a 2nd identical product to troubleshoot my existing ADC Switcher w/o any mention of sending one back or for credit. Even the CS rep remarked that I probably didn't want to do it but it was a suggestion. Don't hold your breath on the integration of Auto-EQ or DVI Detective into the next version of the DL KVM, they've said things in the past about previous products having problems and perhaps addressing them in a future version of the product but they never followed through.
  • n7 - Wednesday, October 19, 2005 - link

    Remind me to never ever purchase a Gefen product.

    Any company that has the nerve to suggest i buy another product to make their own defective product work properly can go DIAF, to put it nicely, LOL.
  • Aquila76 - Wednesday, October 19, 2005 - link

    Try finding a KVM (DVI or not) that works with a USB cordless keyboard & mouse. I tried a Belkin, Tripp-Lite, and IOGear; all would lose or mess up the tracking for both the K & M when I switched away to my other box.
    I have a Logitech Cordless Elite Duo, it has one USB plug that goes to the receiver for the K & M. I think that is what's screwing the KVM switches I've tried, as they apparently need seperate plugs for both.
  • johnsonx - Wednesday, October 19, 2005 - link

    I think your issue is that when you switch your USB device looses power for a moment... that's enough to kill the wireless receiver and make it loose track of the kb and mouse.
  • 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. Reply
  • 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.

  • 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. Reply
  • 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

    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. Reply
  • lopri - Wednesday, October 19, 2005 - link


    $2500 monitor

    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.

  • Questar - Wednesday, October 19, 2005 - link

    Apple has it for $2499 on their website. Reply
  • KristopherKubicki - Wednesday, October 19, 2005 - link

    Market demand is a weak excuse, but really; it's true. The panel Apple uses is really only used for medical imaging. If someone is going to make it cheap though, it's going to be Dell. They will eventually.

  • sprockkets - Wednesday, October 19, 2005 - link

    OK, they are rare, and maybe it wasn't a dual link version, but hell, when you can get a KVM for around what $20 for the VGA version, why bother with $400? Are DVI switchers just going to cost that much since it is digital? Reply
  • Samus - Wednesday, October 19, 2005 - link

    If you have two computers and a 30" display, you're a bastard. Reply
  • bersl2 - Wednesday, October 19, 2005 - link


    You have one 30" Cinema Display, and two computers. What do you do?

    You turn one into a server.

    FWIW, I wouldn't bother with this KVM crap.
  • karioskasra - Wednesday, October 19, 2005 - link

    "You have one 30" Cinema Display, and two computers. What do you do?"

    Well first I'd hit the local bar to try to forget the horrible deeds I had to do to get my hands on that lcd.
  • JarredWalton - Wednesday, October 19, 2005 - link

    What about the potential to simply use shorter cables? Really, it seems like the DVI Detective should just connect inline with the DVI cable and not even require an extra cable. Barring that, a short 5" cable on one side would be able to fix the issue, perhaps?

    I don't know if you can actually find cables that short, but Gefen ought to be able to do that, right? Since you only need to program the DVI Detective when you change monitors, there's not much point in making them more visible. Of course, requiring people to purchase the DVI Detective in the first place on a $400 product is not really acceptable to most users.

    I'd also be interested in hearing how the G5 system fares with a non-ATI card. My own experience is that ATI cards seem to be a bit more picky with EDID information. My (super cheap $25) KVM works fine with NVIDIA cards, but sometimes ATI cards don't know what monitor is attached, defaulting to lowest-common-denominator refresh rates. (I just uncheck the "Use EDID Information" box and manually specify the monitor capabilities in that case, but it's a bit annoying - not sure if anything like that is even an option for Macs, though.)

    Anyway, I need a new KVM, preferrably with four ports and USB+DVI support. Thank goodness I don't need dual-link DVI as well!
  • Beh - Wednesday, October 19, 2005 - link

    well, its not all bad, but i do think it needs work. if they integrate the DVI detective functionality and the auto-EQ in their next version it may be worth looking into. for now, i will pass... Reply
  • MAME - Wednesday, October 19, 2005 - link

    huge piece of crap Reply

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