14 Computer Service and Repair
and allows devices to easily slide into or out of
the PC case. A device installed into the device
bay looks as though it was installed internally.
By installing the device into the device bay, the
problem of long cords running across and around
valuable desk space can be eliminated.
RJ
There are two types of RJ connectors
commonly used with a PC: RJ-11 and RJ-45. The
RJ-11 is used for modem telephone connections. The
RJ-45 is used for network connections. The RJ-11 uses
four conductors and four pins, while the RJ-45 uses
eight conductors and eight pins, see Figure 1-18.
DB
The DB connector looks similar in shape to
the letter D, see Figure 1-19. The DB connector
typically is classified as 9-, 15-, or 25-pin. The DB
connector was once commonly used to connect
items such as a joystick, monitor, or printer. The DB
connection at the back of a sound card is sometimes
referred to as a game port. When a 15-pin D shell
connector is arranged with three rows of five
connections, it is referred to as an HD-15. The HD
Another desirable advantage of USB is that
you can connect up to 127 devices through the
USB port in a daisy-chain fashion. Before USB, it
was possible to run out of ports to support all of
the equipment that might be needed for a special
workstation. For example, a workstation used by
a graphics designer might require connections
to a scanner, digital camera, microphone, laser
printer, color inkjet printer, poster-size plotter
printer, and a digital graphics tablet for freehand
drawings. USB and FireWire ports are capable of
supporting numerous devices required by a single
workstation. Legacy workstations could only be
used to support a limited number of devices.
Device Bay
The device bay is a drive bay designed to
accommodate the easy hot swap of devices such
as hard drives, tape drives, and optical drives. The
device bay is prewired for either USB or FireWire
Goodheart-Willcox Publisher
Figure 1-17. USB ports.
RJ-45 RJ-11
Goodheart-Willcox Publisher
Figure 1-18. RJ-45 and RJ-11 connectors.