What is the difference between both of them? KVM are very expensive, but why? Don't they do the same thing?
the switch is a mechanical switch... kvm is digital with IC switching. KVM can switch with keyboard shortcuts or automaticly, and the mechanical version cant. there is also extra noise introduced with the mechanical version. and i have yet to see a switchbox that will do 2x PS/2s and a VGA at the same time
Switchboxes are also passive, they don't amplify the analog (or digital if it's USB) signals. Digital KVMs do (at least any decent model will). So you can have 10 foot cables on each side of the switch and you won't have any video signal loss or mouse lag or anything. I'm selling one over in the US FS forum by the way...a monster 4 port digital USB and PS/2 KVM...with optional cables for two workstations...[/plug]
http://www.cyberguys.com/templates/searchdetail.asp?T1=105+0194&dept=&search=&child= So say if I wanted to use a usb switchbox to switch (keyboard & mouse) between computers (Mac Mini & PC) would I have a problem with lag or anything? Or If I used VGA switchbox, would there be any loss of detail beacuse of the switchbox?
Well, the problem with switchboxes for devices is, is that you're literally disconnecting the device from one system and plugging it into the other. A lot of software doesn't like this. Yeah, you can plug and unplug periphreals in XP no problem, but it has to readd the hardware every time. Granted it doesn't go through the driver search stuff, but it can take a while for it to recognize it and readd it as a usable device. Digital KVMs emulate the device an all systems, so when you switch to another workstation, the old one still thinks it's connected. Signal loss is going to depend on the length and quality of the cables you are using. If you're trying to use unshielded VGA cables, forget it. You'll need some high quality shielded cables (most cables are shielded with a grounding tube inside, not all have a ferrite bead for shielding) and it probably can't be very long. It's been a long time since I used a VGA switchbox, but I don't remember getting good results. And that was in the old days with low resolutions and refresh rates - you'll probably get crappy picture in newer, higher resolutions. Keyboard and mouse should be fine, those aren't as sensitive to interference. Probably because there's not nearly as much data and doesn't travel as often. Since USB is digital, it won't suffer as much either. Digital signals suffer from jitter caused by interference, but that usually doesn't matter since the receiving end compensates for it. And it wouldn't be traveling very far anyway. So for periphreals a switchbox should be dandy, but VGA will probably be crappy.
Mechanical KVM switches (KVM just stands for keyboard, video, mouse) can not be reccomended for monitor resolutions over 800x600 because of the shadows (signals rebounding) created by the mechanical switch. The electronic KVM uses a chip for switching and has no rebound effect to cause shadows on the monitor.
Which is better compleatly depends on your use and the products available. You wont want a mechanical switch for lots of pc's that are far apart but for just two pc's close together a switch is better imo. You cant use mechanical KVM's for ps/2 based keyboard and mouse, as it could damage the mobo and they are not designed to be reinserted with pc on so probably wont be detected. The redetection for USB is almost instant and is probably less noticable than on your ps/2 keyboard/mouse with a Digital-KVM Thats the main reson all D-KVM's are the type with emulation to fake the disconnected device. TFT monitors and some CRT's have dual inputs, so if you only need two pc's you can get away without a monitor switch of either kind - as you already have one in the monitor. How many resonably priced DKVM's are there, that accept DVI AND USB.. none.
I have used a mechanical switch at 1600*1200 with NO issues, shadowing or ANYTHING. What a kvm does is it emulates a ps/2 keyboard and mouse so both computers think they are connected to a kb/mouse. The deal with PS/2 hardware is that it is NOT hot swappable (like usb) so if you plug it in after the computer is on, it will not be recognised, etc... Also, the keyboard has to be initalised by the PC (i think). The KVM0 lets you switch one kb/mouse combo between two pcs using PS/2 ports. If you are using a USB keyboard amd mouse, use a mechanical switch. if you are using PS/2 keyboard anr/or mouse, you HAVE to use a kvm. The monitor does not care. You could use either type of switch.
Actually, the keyboard and mouse has more problems with my electronic KVM switch than with the mechanical one, you just had to make sure you were "watching" the machine as you turned it on... Agreed some mechanical ones have no shadows, but it's hard to know wich ones without testing, it all depends on the construction of the switch and connections inside the coupling box.
