Everybody has one, or at least knows a friend who has one: an old, slightly out-of-date PC that has been replaced by a newer, shinier model and now lives in a closet or basement. You’ve always hoped you could do something with it, and now’s your chance to take that old computer and turn it into a home network file server, entertainment center or simply run that one program that only works on Windows 95 without cluttering your desk with tons of extra hardware. All you need is a KVM switch.
What is a KVM switch?
Good question. A KVM switch is a piece of computer hardware that allows you to run two PCs with a single keyboard, monitor and mouse. Not only does this save you the space of having a complete set of input and output devices for your new and old PCs (who has room at home for two monitors?), but it also lets you run both PCs at once and switch between them seamlessly. There are many different types of KVM switches, ranging in capacity from a simple two-computer switch, to models that can handle up to 64 computers at once.
Most KVM switches consist of a box with two or more sets of wires(depending on the number of PCs it will connect) for PS/2 and/or USB keyboard and mouse input and video output, two PS/2 and/or input ports and a video-out port. The KVM switch will emulate, or mimic, the input of a mouse and keyboard to each PC, allowing each to boot-up without causing any errors. Once the computers are up and running, a good KVM switch will allow you to switch between computers using Hotkeys, or a combination of keystrokes that you would almost never normally press. For instance, the IOGear KVM switch installed on my two PCs will switch computers every time you tap “Scroll Lock” twice in rapid succession. To switch back, just tap “Scroll Lock” twice again. For the purposes of this article, I will be referencing an IOGear MiniView Micro KVM switch, though the same general installation steps apply to any switch.
Installing a KVM switch
Installing a KVM switch is as simple as installing a standard mouse, keyboard and monitor. First and foremost, make sure that both PCs and the monitor are powered down and preferably unplugged (better to be safe than sorry). Next, plug the monitor, PS/2 keyboard and mouse into the input side of the KVM switch. These should be the only inputs on the switch, and you should make sure to plug the keyboard and mouse into the correctly labeled ports. Some KVM switches may also have speaker output as well, so you should attach the speaker cables as well.
Once all of the peripherals have been attached to the KVM switch (at least the keyboard, video output and mouse), you can start attaching the switch to your PCs. A KVM switch has two sets of identical cables, one for each PC. The most important thing to remember is to keep each set of cables separate. If the cables are crossed, your KVM switch will send you keyboard commands to one computer and your mouse commands to the other. It is a good ideal to separate the cable sets from each other by tying each set together, either with string, twist-ties or zip-ties.
Begin plugging the KVM switch cables into the computer’s one at a time, taking care to attach the cables marked with a keyboard in the keyboard input port and the mouse in the mouse input. It is always a good idea to label the ports on your computer if they are not already labeled. However, if the cables are reversed, the worst that can happen is your PC will give you an error when you boot-up, and you will have to switch the cables to the correct position. Plug the KVM switch monitor cables into each computer, again making sure that the monitor cables are going to the same PC as the matching mouse and keyboard cables.
The final step is to plug in both of your PCs and your monitor and boot-up. On the first boot, there is always the possibility that one of the PCs will not recognize the KVM switch. To remedy this, follow the instructions that came with your KVM switch, or simply try unplugging the cables from the back of the computer and plugging them back in. If unplugging the KVM switch from the PC doesn’t help, try restarting the computer, making sure that the correct cables are plugged into the correct ports. Restarting the PC will reset your KVM switch, allowing it to correctly emulate the mouse and keyboard.
Once your KVM switch is installed, you can start using both of your computers. Got a couple of gigabytes of free hard drive space on your old PC? Make it a home stereo, fill it with MP3s and play music while you work on your other machine. Attach an Ethernet cord or install a WiFi card and use your old PC as a file server where you can store all of your digital photos, music or video files for access from any computer on your home network. If you need to work on the old PC, just use the KVM switch, then switch back to your main computer with the a quick couple of keystrokes. Soon, you’ll be well on your way to a great, easy to use home network.