Controller Cards
Acontroller,a.k.a.adapter,cardisatypeofexpansioncardthatcontainsthecircuitryand
components needed to control the operations of a peripheral device, such as a disk drive.
Controller cards are less common on newer PCs since device controllers are now typi-
cally included in either the system chipset, the Super I/O chip (see Chapter 5 for more
information on chipsets), or on the device itself.
Controller cards are easy to spot in the PC. They have flat 40-wire ribbon cables con-
necting them and the hard disk, CD-ROM, DVD, and floppy disk drives. In many older
PCs,thediskcontrollercardsupportsboththeharddiskdriveandthefloppydiskdrives.
If a CD-ROM device was installed in an older PC, it typically had its own controller card,
but it could also share the common (multipurpose) controller card. On most Pentium PCs
and after, the device controllers are built into the motherboard and chipset. But there are
still some devices, such as some scanners, that require their own controller card.
The SCSI host adapter, which is installed in either a PCI or ISA slot, is not a controller
card, although it does control the SCSI interface chain of devices on the system. SCSI devices
are like IDE (ATA) devices and have their device controllers integrated into the device itself
(see Chapter 9 for more information on IDE and SCSI storage devices).Input/Output (I/O) Cards
I/O expansion cards add I/O ports, such as serial and parallel ports, to a PC. This type of
expansion cards was once commonly found in PCs, but because the ports they add are
typically included in the PC as a part of the motherboard, they are inserted only to upgrade
the existing ports. Both serial and parallel I/O expansion cards are available for either
ISA or PCI buses (Figure 11-11).
You may want to add new parallel ports to a system to add IEEE 1284 capabilities like
ECP (Enhanced Capabilities Port), EPP (Enhanced Parallel Port), and bi-directional data
transfer support.
Cards that add serial and parallel ports are primarily 8-bit ISA cards, but there are
also16-bit and 32-bit PCI cards available, as well as faster interfaces, like the USB or
FireWire, that can be added with a PCI card.
It is possible to add additional serial and parallel ports by connecting a port block into a
USB port. A quick, efficient, and up-to-date way to add additional serial ports is to add a USB
expansion card, like the one shown in Figure 11-12, which typically adds two or four USB
ports to the PC. Then plug a two serial port block into one of the USB ports.Interface Cards
Interface cards are the most nondescript of the expansion cards. In fact, just about any ex-
pansion card can be and usually is classified as an interface card. In general, an interface
card connects any external device, network, or gadget such as a mouse, an external
CD-ROM, scanner, or camera to a PC. Interface cards are also the PC Cards used to
connect external devices to notebook PCs.Chapter 11: Expansion Cards^231