CompTIA A_ Certification All-In-One Exam Guide, Seventh Edition - Michael Meyers [33]
Figure 3-22 Typical bank of 1/8-inch audio jacks
Figure 3-23 Legacy joystick/MIDI port
Network
Networks are groups of connected PCs that share information. The PCs most commonly connect via some type of cabling that usually looks like an extra-thick phone cable. A modern PC uses an RJ-45 connection to connect to the network. Figure 3-25 shows a typical RJ-45 network connector. Network connectors do not have a standard color.
Figure 3-24 S/PDIF connection
Figure 3-25 Typical network connection
* * *
NOTE Modern PCs have built-in network connections, but this is a fairly recent development. For many years, network devices only came on an expansion card, called a network interface card (NIC). The term is so common that even built-in network connections—which most certainly are not cards—are still called NICs.
Mouse
Most folks are pretty comfortable with the function of a mouse—it enables you to select graphical items on a graphical screen. A PC mouse has at least two buttons (as opposed to the famous one-button mouse that came with Apple Macintosh computers until recently), while a better mouse provides a scroll wheel and extra buttons. A mouse uses either a USB port or a dedicated, light-green mini-DIN connector (see Figure 3-26).
Figure 3-26 Mouse with mini-DIN connection
A variation of the mouse is a trackball. A trackball does the same job as a mouse, but instead of pushing it around like a mouse, the trackball stays in one place as you roll a ball with your fingers or thumb (Figure 3-27).
Figure 3-27 Trackball
Modem
The old modem enables you to connect your PC to a telephone. Modems are another easily identifiable device in PCs as they have one or two RJ-11 jacks. One jack is to connect the modem to the telephone jack on the wall. If the modem has a second RJ-11 jack, it is for an optional telephone so you can use the phone line when the modem is not in use (see Figure 3-28).
* * *
NOTE External modems traditionally connected to a male 9-pin or 25-pin D-subminiature port on the system unit called a serial port (shown below in Figure. 3-28). Although just about every external modem today connects to USB, a few computers still come with a serial port for legacy devices.
Figure 3-28 Internal modem
Serial ports are one of the few connectors on modern systems that were also used in the first PCs more than 20 years ago.
Printer
For many years, printers only used a special connector called a parallel port. Parallel ports use a 25-pin female DB connector that’s usually colored fuchsia (see Figure 3-29).
After almost 20 years of domination by parallel ports, most printers now come with USB ports, FireWire, Ethernet, and Wi-Fi 802.11 b/g/n connectivity options. Parallel ports are quickly fading away from the backs of most computers.
Figure 3-29 Parallel port
Joystick
Joysticks weren’t supposed to be used just for games (see Figure 3-30). When the folks at IBM added the 2-row, 15-pin female DB joystick connector to PCs, they envisioned joysticks as hard-working input devices, just as the mouse is today. Except in the most rare circumstances, however, the only thing a joystick does today is enable you to turn your PC into a rather expensive game machine. But is there a more gratifying feeling than easing that joystick over, pressing the Fire button, and watching an enemy fighter jet get blasted by a well-placed Sidewinder missile? I think not. Traditional joystick connecters are colored orange, but most joysticks today connect to USB ports.
Figure 3-30 Joystick
eSATA
More and more PCs are showing up with eSATA ports like the one shown in Figure 3-31. The eSATA is a special connector for external hard drives and optical drives.
Plenty More!
Keep in mind that there are lots more devices and connectors out there. This section includes only