Keyboard/Video/Mouse switch. Any device used to control multiple (n) computers with 1 (or at least some number less than n) keyboard(s), mouse(mice), and monitor(s). Although most used to be manual and have AT-style connections, most versions sold nowadays are either PS/2 or USB based, and have automatic (pushbutton/keyboard control) switching.

Some of the better-known and well thought of brands include:

I have an OmniCube 4-port, and I'm quite happy with it. Several nice touches make it easy to use. First of all, while the four sets of input ports are in the back of the unit, the console keyboard and mouse port are in the front, along with the switch button - this makes it usable as a desktop unit without having cables everywhere. Also, the OmniCube can handle inline controls - hit Scroll Lock twice and it beeps, which means that using the uparrow and downarrow keys will switch between inputs. Very handy if you have the thing stuffed behind your desk. Belkin also makes ADB adapter modules for you older Mac users (like me) - however, they're quite expensive. The only other annoying thing is that the cable sets are pretty expensive over 3 feet in length; they do make up to (I think) 18 foot cable sets, but those cost nearly $90 each.

For those with populous racks, both Belkin and Black Box make 16-port versions, and I believe the Black Box units go up to 48 ports!

danlowlite is not the only one! I too have had this problem with some switches. My OmniView doesn't exhibit this, however. I think the reason is that the high frequencies required by high resolution monitor signals don't pass through cheap or interrupted connections very well. I had this trouble with a no-name beige metal SVGA switchbox, but the OmniView works for me. YMMV.