Chapter 7 Digital Prepress 131
Input Devices
There are a number of ways in which text or
graphics information can be entered into the computer
system. Methods range from manual entry, such as
keyboarding, to electronic transmissions through a
modem.
Keyboard
The computer keyboard is the most common way
of entering text into a computer system. In addition
to standard typing tasks, the keyboard may also be
used to perform special functions through dedicated
keys (such as the delete and insert keys). Special
function keys carry out different tasks, depending on
the program being used.
Mouse
Many computer systems rely extensively on input
from the mouse. This navigation device is especially
necessary for user interfaces and graphics. For
example, a mouse is commonly used to cut content
from one document and paste it into another.
Modem
A modem is an electronic device that converts
digital signals into a form that can be transmitted
over telephone lines, and from phone lines into
the computer system. The technical name for this
device is modulator/demodulator. Modems allow
information to be sent from one computer to another,
over distances great and small.
Scanner
Four types of scanners are used today to capture
images: handheld, fl atbed, fi lm, and drum. Handheld
scanners are small devices that are moved across
the image area by hand. Flatbed scanners process
images that are positioned on a fl at glass surface
or scan area that is stationary. The fi lm scanner is
intended to capture images of various types of fi lm.
The drum scanner scans images that are mounted
on a rotating drum. Some types can quickly convert
an entire page of type or printed material into digital
form, Figure 7-7. Scanners are used extensively for
image input. Scanners are discussed in more detail
in Chapter 8.
Voice Recognition System
The premise of voice recognition technology is to
use voice commands to control devices and to enter
data simply by speaking into a microphone. Some
of the major challenges in using this type of system
include:
• Recognizing the voices of multiple users on the
same system.
• Distinguishing homonyms, such as “there,”
“their,” and “they’re.”
As the technology advances, the use of this
system will extend into common applications within
the industry. Presently, voice recognition is limited to
common computer commands.
Output Devices
Most computer systems are connected to a variety
of output devices, including monitors, printers, and
external processing devices. Some output devices
produce physical material, often referred to as hard
Figure 7-6. The removable storage media commonly
used for digital cameras, Personal Digital Assistants,
and computer systems pack a great deal of capacity
in a small space. Flash drives and memory cards are
available in many different designs, all of which offer
easy data transfer and portability. Storage capacity
ranges from 1 to 64 GB.
modem: A device used with computers to send and receive
digital information through telephone lines.
output device: A piece of equipment used to display,
produce, or transfer information processed by a computer,
such as monitors and printers.