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CompTIA A+ Certification All-in-One Exam Guide

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Whenever you’re dealing with a device that isn’t playing nice, you need to

remember that you’re never dealing with just a device. You’re dealing with a

device and the port to which it is connected. Before you start troubleshooting

the device, you need to look at the issues and technologies of some of the

more common input/output (I/O) ports and see what needs to be done to keep

them running well.

Serial Ports

Techs at times have to support or service older gear, such as installed pointof-sale

systems or networking components soldiering on in the background.

Many of these old devices connect to computers using serial connections,

which use the Recommended Standard 232 (RS-232), introduced way back in

1960. A serial port manifests as a 9-pin, D-shell male socket, called a DB-9

or an RS-232. You won’t find serial ports on anything made in the last

decade, but CompTIA thinks they’re important enough to include in the A+

1001 objectives. Figure 10-1 shows a serial connector on a cable and a DB-9

port.

Figure 10-1 DB-9 connector and port

EXAM TIP You don’t need to know how serial ports work to get through

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