The 4-pin power connector is the same type used on most internal peripherals, such as
the hard disk drive or floppy drive. The other connections or jumpers on the drive are
dependent on the type of interface in use. The two most popular types of interfaces are the
IDE/ATAPI (Integrated Drive Electronics/AT Attachment Package Interface) and the
SCSI (Small Computer System Interface). An ATAPI drive uses a standard 40-pin data
connector and jumpers to set the drive as either the master or slave device. A SCSI drive
uses a 50-pin connector and jumpers to set the device ID and termination, identities
required in SCSI device chains (see Chapter 9 for more information on SCSI devices).
ATAPI is an interface between the PC and the CD-ROM drive. This interface is also
used for tape drives. ATAPI adds some additional commands to the standard IDE inter-
face that are needed to control a CD-ROM drive. SCSI is an interface type that allows the
PC to communicate with peripheral hardware, including disk drives, tape drives,
CD-ROM drives, and more.
A CD-ROM also has a thin audio connector that is used to connect it to a sound card
(see Figure 10-9). The audio connector is either a three- or four-wire cable that sends the
CD’s audio output directly to the sound card so it can be recorded on the PC or played
back on the PC’s speakers.Logic Board
Every CD-ROM drive contains a logic board that includes the circuitry and controllers used
tocontrolthedriveandtheinterfacetothePC,whichisusuallyeitherIDE/ATAPIorSCSI.Single and Multiple Drives
By far the most common CD-ROM drives can only load a single CD at a time. However,
some drives can handle two, four, or even more discs at once. The primary benefit of a
multidisc CD drive (see Figure 10-10) is it allows you to access multiple discs, although(^214) PC Hardware: A Beginner’s Guide
Figure 10-9. The CD audio connector cable