3.4. Plugging Two PCs into One Monitor
Sometimes you end up with more PCs than monitors . For instance, some households keep their old PC's monitor when buying a new PC, effectively decapitating the old PC. In other cases, folks share their desktop PC's monitor with their laptop. And some families share a monitor with the kidsif they can get away with it. Whenever you share a monitor between two PCs, a KVM (Keyboard Video Mouse) switch (Figure 3-6) spares you the hassle of crawling behind the desk to switch the cables from one PC to the other.
You plug your monitor, mouse, and keyboard into the switch, which usually costs between $20 and $50. Then, on the other end of the switch, you get two sets of cables: one for each PC's monitor, keyboard, and mouse ports. To work on the PC you currently see on your monitor, start working as normal, typing and moving your mouse.
When the kids want to play with the other PC, press a button on the switch or type a certain key sequencethe Scroll Lock key twice, for instance. That places the second PC's screen on the monitor, letting the kids do their homework.
Figure 3-6. This Linksys KVM switch, available for under $40, lets two PCs share a single monitor (and a mouse and a keyboard, for that matter). Plug your monitor, mouse, and keyboard into the switch. Then, plug the switch's cables into the monitor, mouse, and keyboard ports of the two PCs. To switch between PCs, push a button on the switch or type a special key sequence on your keyboard.
Some businesses juggle dozens of PCs with one KVM switch, letting one operator handle any problems that crop up with computers that are otherwise unattended.
Admittedly, a KVM switch comes with a few drawbacks. Unless you connect the two PCs to a network (Section 14.1), you can't copy information between them. And some wireless keyboards and mice don't work well when plugged into KVM switches. But like all niche products, a KVM switch provides a handy solution under the right conditions.
Sharing a monitor can be more practical than it first sounds. In some setups, for instance, a PC serves only as a backup system (Section 15.1), or it sends music and photos to a TiVo or other entertainment center. Since these PCs usually run unattended, a $30 KVM switch makes more sense than a second $250 monitor.