Section 18.2. Installing Cards in Expansion Slots: All Versions

18.2. Installing Cards in Expansion Slots: All Versions

Modems and adapter cards for video, TV, sound, network cabling, disk drives, and tape drives generally take the form of circuit boards , or cards , that you install inside your PC's case. These slots are connected to your PC's bus , an electrical conduit that connects all the components of the machine to the brains of the outfit: the processor and memory.

The two common (and mutually incompatible) kinds of slots are called ISA and PCI . The ISA bus (Industry Standard Architecture) has been around since the dawn of the PC in the early 1980s. PCI (Peripheral Component Interconnect) is newer and offers much better speed. Most computers in use today have both kinds of slots.

Note: There's also a third type of slot in many of today's computers, called AGP (Accelerated Graphics Port). This slot is almost always occupied by a graphics card.

Knowing the characteristics of the different bus types isn't especially important. What is important is knowing what type of slots your computer has free, so you can purchase the correct type of expansion card. To do this, you'll have to open your PC's case to see which type of slots are empty:

The plastic wall around an ISA slot is usually black. It has metal pins or teeth in the center and a small crossbar about two- thirds of the way down the slot. On some older computers, there may be shorter-length ISA slots with no divider.
The plastic wall around a PCI slot is usually white or off-white, and shorter than an ISA slot. A PCI slot has a metal center and a crossbar about three- quarters of the way along its length.

Installing a card usually involves removing a narrow plate (the slot cover ) from the back panel of your PC, which allows the card's connector to peek through to the outside world. After unplugging the PC and touching something metal to discharge static, unwrap the card, and then carefully push it into its slot until it's fully seated.

Note: Depending on the type of card, you may have to insert one end first, and then press the other end down with considerable force to get it into the slot. A friendly suggestion, however: don't press so hard that you flex and crack the motherboard.