Belkin OmniView SOHO DVI/USB KVM Switch Review
June 15, 2004
Well, there’s a mouthful of acronyms for you. For those unfamiliar, a KVM switch is a device to switch a Keyboard, Video monitor, and Mouse between several computers. DVI in this case stands for “Digital Visual Interface”, a standard for connecting computers to (mostly) LCD monitors, and of course USB is Universal Serial Bus and SOHO stands for “Small Office – Home Office”.
Regular readers may recall that a short time back I ended up replacing a dying old Viewsonic 19” CRT with the excellent Princeton VL1916 19” LCD monitor. Well, of course one thing leads to another, and I decided that it’d be convenient to be able to use this with both my desktop and my PowerBook.
I’ve used KVM switches in the past, but those were the dark days of the technology—not-too-bright mainly mechanical switches, usually with a lot of quality loss on the VGA signal. They were annoying, but handy under certain circumstances.
Times have changed…
Both my desktop and the PowerBook have the option of putting out a DVI signal, and I’ve now got a monitor that will take DVI input. Why this is important requires a little explanation…
VGA signals are analog signals. In simple terms, your video card converts the digital image produced by your computer into a series of voltages for Red, Green and Blue. This signal is then converted by the CRT into the image. The VGA signal is susceptible to noise and interference just like any analog signal.
LCDs, on the other hand, are inherently digital. If you hand a VGA signal to an LCD monitor, it has to convert the analog signal (back) into a digital image. With DVI, your video card sends a digital signal direct to the LCD monitor, skipping the conversion to analog and back to digital, and giving you a “truer” picture without the “interpretation” of all that conversion.
Also important, it means that the signal between the two is digital, and not susceptible to the same kind of interference as analog.
Consider an analog cordless phone versus a digital cordless phone—with the analog phone, you get all of the “radio” noise—static, hissing, etc. With digital, it mostly either works 100%, or (with the exception of some artifacts at the very fringe) it totally fails. This is because digital signals can be error corrected.
What all of this means is that a DVI KVM switch, unlike it’s VGA brethren, should put out an image pretty much identical to what you’d get without it.
So, I decided to give one a try. I also wanted to use USB for keyboard and mouse, since both the Mac and the PC support them. This narrowed down the playing field considerably. The few KVMs that support DVI and USB are fairly expensive, in the $200 – $400 range. The Belkin two-port switch (model F1DD102U), however is routinely available via mail order suppliers for $150 – $175.
Note: Bear in mind that there are some hidden costs to a KVM switch—you also have to factor in the cost of DVI and USB cables to the switch, and any additional cables you need to hook up the monitor, keyboard and mouse. Belkin also offers a cable pack for this purpose, but it’s considerably more expensive than purchasing quality cables separately.
The unit itself is nice, albeit a little “exotic shaped”. The back cover lifts off to reveal the connector bay, and serves to force the cables into a nice bundle when it’s in place.
The switch takes DVI, USB (1 or 2), and stereo audio connections from each machine, and has a single DVI output, Keyboard USB connector, Mouse USB connector, “Other” switched USB connector, and stereo audio out. The “other” connector is a nice touch that allows you to switch additional USB devices, such as printers, etc.
Setup is easy; run your cables, plug them in and go. There is no software to install (the unit comes with a special serial cable to re-flash the ROM, but my unit came with the current release).
Switching between the computers can be done by pressing the switch on the unit corresponding to the machine you want to use, or by pressing the scroll lock key twice, and hitting the up or down arrows. Switching is NOT instantaneous—the screen blacks for several seconds when you switch.
Video quality is as good as I expected—I see no difference between using the KVM or not. I’m a trifle disappointed that the unit is not transparent to the USB keyboard, however. Since I wanted both PC and Mac functionality on the keyboard, I’d gone with a Logitech keyboard that supported both. Unfortunately, none of the “specialty” functions on the keyboard are supported—in fact, Logitech’s driver can’t find a Logitech keyboard on either machine. I presume this is due to the unit filtering the keyboard output looking for the scroll-lock switch sequence.
This is a particular pain with the Mac, since the keyboard maps Command to the “windows” key and Options to the Alt key—ass-backwards from what I want, something the Logitech driver could have corrected. The solution to this is the excellent little freeware uControl pref panel, which can swap these keys on a keyboard by keyboard basis (meaning the notebook’s keyboard stays correct). It can also be used to disable the Caps Lock, a Good Thing™.
The only other problem I’ve found is that once in a blue moon, when I switch to the PC it doesn’t find all of its USB devices—most notably, the mouse. This would appear to be due to the real aggressive power management settings I’m using, and at the moment, I’m just tolerating it. Often it will pick the mouse back up in a few seconds. If not, hey, it’s Windows—it’s probably overdue for a reboot anyway…
One thing I’ve not mentioned is the audio switching, mostly because I haven’t tried it—I have both machines tied into my speakers, meaning that I can start a playlist on iTunes on the PowerBook, and switch over to the Windows box and still listen. I can only assume that the audio switching works as advertised, but I can’t say anything regarding how it affects sound quality, if it does at all. If you’re picky about sound quality, then you probably are outputting 5.1 audio, in which case switching two channels isn’t going to work well for you anyway.
All in all, the unit functions very well; if you’re in the market for a DVI/USB KVM switch, I’d have to say that this unit is well worth your time to give it a try.