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USB KVMs Compared
EconolineCrush writes "KVM switches have always been a great way to control multiple machines, and now they're coming with all sorts of cool USB peripheral sharing and audio switching functionality. The Tech Report has a compared a couple of the newest KVM switches from Belkin and IOGear that're worth a look if VNC just doesn't do it for you."
I've got one of these hooked up betwen my old ass G3/233 (with Mac OS X 10.1.5 and a combo USB/Firewire card, which works great) and my XP box. Plug commonly used devices into the extra ports on the front, like my Epson printer and my Handspring Visor, and it's good to go. I haven't had one single problem with the unit so far, and there was even a $20 rebate, so it was under $100 too. :-)
KVMs are good, and they certainly have a variety of specialized uses, but they're not versatile enough, in my opinion. For example, in situations where two computer might need to both be used at once. What do you do then?
I've been looking around for solutions to this problem, because I've been thinking of opening a cybercafe, and I found something called BeTwin.
BeTwin is like the inverse of a KVM switch. Instead of having one keyboard, monitor, and mouse control one of a bunch of machines.. it turns a single machine -into- the bunch of machines.
Licences are $80 a head, and you can have up to 5 people independently using a single Windows 2000/XP machine just by plugging 5 USB keyboards, 5 USB mice, and 5 graphics cards into a computer (5 USB speakers too, if you think the USB bandwidth will take it!).. absolutely ideal for cybercafes where processing requirements on each station are low.
I have decided to go with the Linux route, rather than pay these fees, but thought I'd share it anyway.
mogorific carpentry experiments
I use KVM switches at work and wish I had one at home. The ones I use are fairly expensive (Blackbox... they make lots of server products) and still leave something to be desired. On high resolutions, it takes a couple of seconds to switch between machines and even after paying so much, you can make out that the image is a little blurred on a 21 inch LCD (from Dell). And most of them dont work too well with laptops.
That said and done, I have to add that they are indespensible. Its amazing how much time it saves especially with keyboard shortcuts (you press Control-Control to get to the KVM and then a letter for the computer you want to switch two). Plus its essential in server rooms where these boxes can be cascaded to 64 or 128 machines. Now if only the good ones were a little bit more affordable for the rest of us....
KVM switches are okay if you're just trying to avoid having more than one monitor for a couple of boxes you sit in front of, but they suck for managing a lot of hosts in real production work. I find that using a PC Weasel and a terminal server works a lot better than a KVM switch for remote management of Unix boxes running on PC hardware. KVM switches are okay some of the time, but PC Weasels rock!
I've got an IOGear 4-port PS/2 KVm switch at home, and I've *never* had any problems with losing the mouse/keyboard connection on it.
In fact, the only problem I've ever had with it is when my 6-year-old AlphaServer refused to recognise my keyboard when connected to the switch, but all the other hardware I've tried with it (including an Alpha Miata workstation) have worked fine.
We have over 100 KVM switches in our building. in 30 different labs. Some are for SUN, some HP, most for PCs, and none of them ever give us problems. However, while we are not using the top of the line matrix KVMs, we are not using the SOHO crap that the artical rates. Our switches are setup to handle more than one user, 2 or 4, and control 8 to 32 machines. I am looking for a cheep way to buy one of these monsters for my home. The cheapest 4 user by 16 port system I have found is $3999. All of the switches we have can handle 1600x1200, and allow for PS/2 | DINN | serial style keyboard/mouse connections. All of them have on screen display, however none of them have USB or sound support. If you as a reader are looking into KVM switches, but don't want the sound of humming boxes under your desk, check out the longview extenders from . You can put this bad boy 200ft away from your kvm switch, and still view your screen at 1600x1200. We play FPS'ers via these titans all the time, with no loss of res, or screen update speed.
Also, while VNC (slow screen updates), is by far the greatest free tool of it's kind I have ever seen, there are cases where you really really want to be at the console, and yet still keep your boxes in a controled environment.
I have a Linksys KVM100SK 2 port KVM. It doesn't do USB, but it carries 1600x1200 video at 75Hz rather nicely. It's also cheap, comes with well shielded cables, supports my logitech wheel mouse in both Windows and Linux (using MS drivers on the OS), and doesn't require external power.
I've found lots of the problems aren't so much the KVM as the cables. I got a KVM that came with a full set of cables, but they ghosted. I also bought some cheap VGA cables and they did the same thing.
However, when I bought some heavier duty cables with the ferrite cores on them, all the problems went away. (FYI I bought them locally at Action Computer in Sunnyvale, CA and they weren't too expensive)
Check your cables.
The article states:
Unfortunately, both of these switches require large, boxy power adapters, the kind that don't tend to fit well in most surge protectors. Ideally, I'd like to see power pulled directly from one of the connected computers, but I'd settle for a power connector that moves the box away from the plug itself.
Perhaps my version of the Belkin KVM switch is different from the one they reviewed, but mine requires no external power. It works exactly as they wished it would... using power from the systems themselves.
I have a Windows PC using PS/2 plugged into port 1, an Apple G4 using USB into port 2, and a Linux box using PS/2 in port 3. The keyboard and mouse are PS/2 and the Belkin box effortlessly translates between them.
The problems they mention with USB peripheral disconnect is likely because the reviewer has connected the USB peripherals to the keyboard. You have to think of the KVM as its own USB device and not a hub. It's a KVM switch not a KVM-CD Burner-Digital Camera switch.
I can't comment on the other switch they review, but I love my Belkin KVM switch and I'd recommend it, especially if you have a mixed installation as I do. It works great with very few problems.
All opinions presented here aren't mine.
There ya go, home-made long video non-sucky cables made easy.
If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC
I just finished returning the Belkin switch they reviewed here. I found it to be unusable, because of some major shortcomings.
The first thing was that it didn't work with my keyboard (logitech wireless). The F7 key was useless when plugged into the KVM. This was relatively minor, and they promised a firmware upgrade to fix it. Also, for those that care (I'm not one of them) the "internet keys" don't work.
The other problem I had was also keyboard related. The KVM has a keyboard emulator, which sends keyboard events to the computer, after receiving them from whatever keyboard you have plugged in. If you hold down a key for 3 seconds, the keyboard emulator fakes a key release. So scrolling stops after 3 seconds, and if you're ctl-clicking to select stuff, and you take more than 3 seconds to do it, suddenly the ctl-key is no longer pressed down, and you select just one item. I got the impression that this wasn't going to be fixed in firmware, but rather in the next revision of the product.
Also, the response time was sluggish at best, typing felt like i was in an ssh session over a slow link. Oh, and keys stuck sometimes.
I was planning on getting the IO Gear one instead, as I am told it doesn't have the same shortcomings. Here's hoping.
I have used switches by Belkin, IOGear, Cybex, and a few others and they aren't even close in quality.
Only the IOGear does not display any video ghosting. IOGear video is rock solid with no fuzziness.
I switched to USB after I saw that IOGear uses 'USB sniffing". This neat feature eliminates that 3 to 4 second delay that every other USB KVM has and makes the switch as responsive as a PS2 switch.
IOGear has top quality stuff but their cables are a bit expensive.
The scroll lock hotkey on the Belkin's can cause the console to get stuck in linux, sometimes you have to hit the button on the KVM to unfreeze it - which can be a pain if you plan on only using the hotkeys and have the KVM in a out reach spot on your desk.
The belkin SOHO series (which I am using now) don't seem to reset PS/2 mice as reliably as the older Omnicubes (which I also use). Although, you don't need AC power for the SOHO series (it will draw power from keyboard ports). I had to return two units (over the course of 1.5 years) that would change channels (with loud beeps) in the middle of the night randomly - even though the PCs were off and wouldn't stop until I unplugged every single cable (including monitor). Adding an AC adapter from a spare omnicube fixed that problem.
Belkin does have a 3 year warrenty on their KVMs though, which has proven helpful for me.
Don't believe the hype. The guy asking specifically mentioned LCD screens - and they tend to look like hell when you put them through a KVM, especially one of these low end KVM switches. The reviewer was using a CRT screen, unless I'm mistaken.
I tried the previous Belkin USB KVM. It sucked. Apart from failing to switch smoothly at all - the keyboard would constantly disappear on switching and then I'd have to actually move it to another port to get it to work - the video signal was terrible. I was running at 1024x768@70Hz. It was blurry as hell.
I contacted Belkin to tell them it was the least impressive product I'd ever bought, detailing my problems.
On the monitor front, they replied that the switch was not designed to be used with LCD screens, which was why the quality was so bad.
Seriously, when you're used to pin sharp LCD displays, putting them through a KVM and turning them into something that looks like a 6 year old CRT is not such a great idea.
Maybe Belkin have fixed this issue with the new one, but bear it in mind if you have an LCD screen.
I actually have two monitors and one kbd/mouse, and use a simple Belkin no-frills USB switch with the kbd/mouse. It works like a charm - mainly because I don't think it tries to be too clever.
Oh yes - the KVM also looked rubbish on my CRT monitor too - but I traced this to the 'official' Belkin VGA cables - they sucked too. Replacing them with other (not expensive) makes of VGA extension leads improved the video quality on the CRT enormously. This was trivially proved by just using the leads as extension leads, taking the switch out of the equation. When using the Belkin leads, video quality was crap. Again, maybe they've fixed that now - I don't know - but it's something else to be aware of.
Tim
It was cheap when cheap mattered, and it replaced a connection without changing the way it worked. And for the record, the old connections were not RS-232 ports, so the question is a bit off the mark. Yes, they had some RS-232 components, but they weren't full-featured.
If memory serves, IBM invented this cable format for the PS/2. (You do remember IBM had a computer called the PS/2, right?) This particular connector might have been adapted from something else (strong resemblance to a Mac kbd/mouse connector, as I recall), but the big public play was with the PS/2. It was smaller, cheaper, etc, than the AT keyboard connector, and therefore a win all around. IBM then quickly adapted it for use with their `standard' PCs, and everybody followed. (Again, this was back in the days when IBM did something and everybody followed.) It was (and is) signal-compatible with the old keyboard, and I've still got a few of those ATPS2 keyboard adapters around somewhere in the dungeon.
At the time the AT-style keyboard connector was put on PCs (early 1980s), nobody ever dreamed we'd be having roomfuls of these things all cabled up to a single monitor/keyboard/mouse. The computers were too expensive for a person to own more than one, and not powerful or reliable enough to put into racks and stacks to provide specialized services. The kind of switching talked about here just wasn't envisioned, and in fact, would have been considered insane. Putting more expense into the component so it could be hot-swapped (and making the appropriate O/S changes) was simply not worth doing.
But eventually technology catches up, and the marriage of USB with keyboard/mouse permits the right thing to happen. One could argue that you ought to simply be able to plug/unplug the keyboard from USB host to USB host, and in fact, you can do that with some of them. But that still doesn't solve your monitor connection problems, and last time I checked, SVGA didn't work over USB. So a single switch that moves 3 components simultaneously is a big win.
I looked over the article posted at the top, and am pretty impressed. USB KVM switches are a great idea, and after reading over the above articles, I want one. In fact, I want both of 'em, because each has some very cool features.
Hmmm... so I guess I'll wait until the next generation comes out, when each company adds features from the other. :-)
If you only switch occasionally, this might be ok. If you frequently switch (as between RISC workstation and PC), it's unacceptable.
4% of USB KVMs are actually just simple mechanical switches. They have all the same problems as above, plus, striclty speaking, they violate USB rules, and can have nastly malfunctions if they don't have correct precedence for power-on/off (as USB connectors do).
1% of USB switches, just now entering the market, have "spoofing", aka "sniffing", aka emulation of devices. A correctly implemented spoofing switch never lets any host see a disconnect. Designing this is far from trivial. USB is complex, and the varieties of keyboards and mice are effectively infinite if you're trying to chase them all for purposes of emulation.
In addition to the IOgear mentioned above, there is only one other spoofing switch that I'm aware of, and it isn't fully debugged yet.
In the meantime, I recommend:
Wait for this USB KVM situation to get sorted out. And it will need to soon, as PS/2 ports will be vanishing from new machines next year (and already have from many 64-bit platforms).