FAQ - KVM switches
by Lee Penrod, Chief Forum Moderator
The following questions are common ones that have been asked on our Forum. I have posted the questions and answers here so that you may find them easier.
What is a KVM switch? KVM stands for Keyboard, Video, Mouse. In the strictest definition of the term, a KVM switch allows you to use one Keyboard, Monitor, and Mouse to operate several computers.
What's the difference between a mechanical and a non-mechanical/smart/intelligent KVM? A mechanical KVM acts sort of like a on/off switch. When you change from one system to another using the switch on the KVM, a mechanical KVM mechanically connects your devices from one system, and connects them to another. Unfortunately, some computers are very bad about hot swapping some devices like ps2 mice / keyboards and may crash when you change from one device to another when using a mechanical KVM. Additionally, you may lose settings that affect the accuracy of your mouse when performing such a mechanical switch.
A intelligent KVM performs the connection electronically inside the KVM such that the all systems connected to the KVM think they are always connected to your devices. The KVM does this by spoofing/simulating the devices so that the attached systems never know that a switch occurs. This simulation is a lot less harsh on the attached systems. The draw back of a intelligent KVM is really only in the cost of them. Intelligent KVMs generally cost significantly more then mechanical KVMs.
I have USB devices that I want to switch between two systems. Is there anything I should be concerned about? If you have USB devices like USB keyboards / mice then the first thing you should make sure you do is to purchase a KVM that has USB support. Older KVMs do not have USB support. Most KVM manufactures now make KVMs support USB, and some KVM makers even make USB only KVMs. One of the more popular USB KVM makers is Iogear.
One other concern regarding USB devices and KVMs is the operating system. Generally if you are planning to use a KVM with USB it is advisable to use an operating system newer then Windows ME. Windows ME/98se/98 all follow the old fashioned method of device detection and may actually lock up momentarily right after a switch as the operating recognizes the USB device. Windows 2000/XP use a better system for USB detection and will almost always do detection very fast in the background, often without pulling up any device notification boxes.
I'm looking at a KVM on your site. Is it Mechanical or Intelligent? As a rule of thumb, if a device is not marked as mechanical, then it is an intelligent KVM. If there is any doubt please ask on our Forum.
Are there any other considerations before I make my purchase? One major consideration you should make before purchasing a KVM is how many ports do I need? It is much cheaper in the long run to buy more ports then what you think you need now, then to go out later and buy a larger KVM to replace a smaller one. One major consideration along this idea is the concept of stack ability often high end KVMs by manufacturers like Belkin will be stackable. If you purchase a stackable KVM, and you need more ports you could potentially purchase another KVM and chain/stack it together with the old KVM in much the way one can chain Ethernet/USB hubs. If you are purchasing KVMs for a large machine room / server room then stackable KVMs are a good way to go.
How do I switch from one system to another with the KVM? KVM's generally have two ways to switch from one system to another: by pressing a button on the KVM or using a hotkey. Hotkeys for some KVMs are preset, and are listed with the KVM documentation while others can be custom set in some manner. High end KVMs may even have an on screen display that you can bring up via hotkey when you can select the system via an on-screen menu.