Datasheet

Input and Peripheral Devices 63
One cable that deserves special mention is the null modem cable. It allows two comput-
ers to communicate with each other without using a modem. This cable has its transmit and
receive wires crossed at both ends, so when one entity transmits on its TD line, the other
entity receives it on its RD line.
Unshielded twisted pair (UTP) is the most common type of cable used for network cabling.
There are various categories of network cabling; the category required for 10BaseT/100BaseT
networking is Category 5, often shortened to Cat 5. There is also a Cat 5e cable type, which
is used for higher-speed Ethernet such as Gigabit Ethernet.
Miscellaneous Peripherals
There is almost no limit to the number, or type, of peripherals and input devices that
can be connected to a computer. CompTIA wants you to know that the day when only
the keyboard and mouse were connected have gone by the wayside.
Among the many devices that can be connected today are the following:
Bar code reader, used for scanning barcodes.
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Biometric devices, used for authentication purposes; among the most common are
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thumb readers included with a number of laptops.
Capture cards, used for capturing video, typically using RCA connectors.
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KVM switches, which allow you to use one keyboard, video, and mouse set with a
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number of PCs.
Multimedia (such as web and digital cameras, MIDI, microphones); used to input video
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and audio, and commonly use USB or FireWire connections.
Touch screen, available for desktops and laptops; this adapter allows you to interact
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with the software by touching the screen.
TV tuner cards, used to receive television signals on the computer; most include a
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capture card built in.
Exam Essentials
Know what RJ-45 connectors are used for. You’re likely to be asked what type of connec-
tor would be used to attach a network connector to a wall jack.
Know what PS2/mini-DIN connectors are used for. You’re likely to be asked what type of
connector would be used to connect a keyboard or mouse to the back of a PC.
Know what RJ-11 connectors are used for. You’re likely to be asked what type of connec-
tor would be used to connect a modem to a telephone jack.
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