COMPUTER APPLICATIONS Waxahachie High School

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COMPUTER APPLICATIONSWaxahachie High School

• Input/Output Devices
• TA TEKS (1)(B), (2)(A), (2)(B), (2)(C)

Source Computers Tools for an Information Age
(Capron and Johnson)
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INPUT/OUTPUT DEVICES

• LESSON OBJECTIVE
• Explain how data is input into a computer system
  and differentiate among various input equipment.
• Describe how a monitor works and the
  characteristics that determine quality.
• List and describe the different methods of
  computer output.
• Differentiate among different types of printers.

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INPUT/OUTPUT DEVICES
A source document is the original written data to
be input into the computer. A keyboard is a
common input device that may be part of a
personal computer or a terminal connected to a
remote computer. Cordless keyboards communicate
with the system unit via infrared or radio waves.
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INPUT/OUTPUT DEVICES
Standard Keyboard
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INPUT/OUTPUT DEVICES
Specialized Keyboard
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INPUT/OUTPUT DEVICES
Folding Keyboard
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INPUT/OUTPUT DEVICES
Ergonomic Keyboard
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INPUT/OUTPUT DEVICES
Keyboard Areas
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INPUT/OUTPUT DEVICES
A pointing device is used to position a pointer
on the screen. The pointer can have a number of
shapes but is most often an arrow. You move the
pointer and then click the button to place the
insertion point, or cursor, at the pointer
location. An icon, a pictorial symbol on a
screen, can be clicked to invoke a command to the
computer.
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INPUT/OUTPUT DEVICES
A mouse is an input device whose movement on a
flat surface causes a corresponding movement of
the pointer on the screen. A mechanical mouse has
a ball on its underside that rolls as the mouse
is moved. An optical mouse uses a light beam to
monitor mouse movement. A cordless mouse uses
infrared or radio waves rather than a cord to
send signals to the computer.
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INPUT/OUTPUT DEVICES
Optical Mouse
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INPUT/OUTPUT DEVICES
A trackball is like an upside-down mechanical
mousethe ball is rolled with the hand.
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INPUT/OUTPUT DEVICES
A touch pad uses finger movement on its surface
to control the pointer.
A pointing stick is a small pressure-sensitive
post mounted in the center of the keyboard that
uses pressure to indicate the direction of
pointer movement.
Pointing Stick
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INPUT/OUTPUT DEVICES
A joystick is a short lever with a handgrip that
is moved in one direction or another to move the
pointer.
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INPUT/OUTPUT DEVICES
A graphics tablet, also called a digitizing
tablet, is a rectangular board that contains an
invisible grid of electronic dots. As the user
moves a pen-like stylus or a mouse-like puck with
crosshairs around the board, the dot locations it
passes over are sent to the computer.
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INPUT/OUTPUT DEVICES
Graphics Tablet
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INPUT/OUTPUT DEVICES
Touch screens enable the user to input
information by pointing to locations on the
screen with a finger.
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INPUT/OUTPUT DEVICES
Some screens use a light pen as the input device,
enabling more precise pointing.
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INPUT/OUTPUT DEVICES
Magnetic-ink character recognition (MICR) allows
a machine to read characters made of magnetized
particles, such as the preprinted characters on a
personal check. Some characters are preprinted,
but others, such as the amount of a check, are
added by a person using a MICR inscriber.
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INPUT/OUTPUT DEVICES
MICR Symbols
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INPUT/OUTPUT DEVICES
An optical scanner can convert text or even a
drawing or photograph into computer-recognizable
form by using optical recognition, a system that
uses a light beam to scan input data and convert
it into electrical signals that are sent to the
computer for processing. In a process called
document imaging, a scanner converts those papers
to an electronic version, which can then be
stored on disk and retrieved when needed.
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INPUT/OUTPUT DEVICES
A flatbed scanner typically scans a sheet at a
time. A sheetfed scanner uses motorized rollers
to feed the sheet across the scanning head. A
handheld scanner, the least expensive and least
reliable of the three, is handy for
portability. Optical character recognition (OCR)
software can convert the digital picture produced
by the scanner into text for processing.
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INPUT/OUTPUT DEVICES
Flatbed Scanner
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INPUT/OUTPUT DEVICES
Optical mark recognition (OMRalso called mark
sensing) devices recognize marks on paper.
Optical character recognition (OCR) devices read
special characters, such as those on price tags.
These characters are often in a standard typeface
called OCR-A. A commonly used OCR device is the
handheld wand reader.
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INPUT/OUTPUT DEVICES
Handheld Wand Reader
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INPUT/OUTPUT DEVICES

• A bar-code reader is a photoelectric scanner used
  to input bar codes, patterns of vertical marks
  one standard code is the Universal Product Code
  (UPC) that identifies a supermarket product.
• Some optical scanners can read precise
  handwritten characters.

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INPUT/OUTPUT DEVICES
Laser bar code scanner, often seen at supermarket
checkout counters, reads the products Universal
Product Code (UPC)
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INPUT/OUTPUT DEVICES
Voice input, or speech recognition, is the
process of presenting input data to the computer
through the spoken word. Speech recognition
devices convert spoken words into a digital code
that a computer can understand. The two main
types of devices are discrete word systems, which
require speakers to pause between words, and
continuous word systems, which allow a normal
rate of speaking.
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INPUT/OUTPUT DEVICES
A Microphone is an input device for speech
recognition.
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INPUT/OUTPUT DEVICES
A digital camera takes photos that are stored
internally on a chip or card, and then sent
directly to your computer, where they can be
edited and printed. Digital images are composed
of pixels. The number of pixels determines the
resolution, or clarity, of the image. Digital
camera resolution is normally expressed in terms
of megapixels, or millions of pixels. Images must
be downloaded, or transferred, from the camera to
a computer.
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INPUT/OUTPUT DEVICES
Digital video consists of a series of still
images, called frames, that are displayed rapidly
enough to give the illusion of motion. Web cams
are inexpensive video cameras that capture images
typically transmitted on the Internet. A video
capture card accepts an analog signal from a
video source such as a TV or video camera and
converts it into a digital signal for processing
by a computer.
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INPUT/OUTPUT DEVICES
The monitor features the computers screen,
includes the housing for its electrical
components, and often sits on a stand that tilts
and swivels. Screen output is known in the
computer industry as soft copy because it is
intangible and temporary, unlike hard copy,
produced by a printer on paper, which is tangible
and can be permanent.
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INPUT/OUTPUT DEVICES
A computer display screen that can be used for
graphics is divided into dots that are called
addressable because they can be addressed
individually by the graphics software. Each
screen dot is called a pixel. The more pixels,
the higher the screen resolution, or clarity. Dot
pitch is the amount of space between the dots on
a screen. A liquid crystal display (LCD) is a
type of flat-panel screen found on laptop
computers and on some desktop computers.
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INPUT/OUTPUT DEVICES
LCD Monitor
CRT Monitor
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INPUT/OUTPUT DEVICES
Printers produce printed paper output and can be
classified as either impact printers, which form
characters by physically striking the paper, or
nonimpact printers, which use a noncontact
printing method. Line printers are impact
printers used on mainframe systems that print an
entire line at a time. Dot-matrix printers use a
print head containing one or more columns of pins
to produce images as a pattern of dots. Laser
printers and ink-jet printers are nonimpact
printers.
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INPUT/OUTPUT DEVICES
Laser Printer (works like a photocopy machine)
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INPUT/OUTPUT DEVICES
Ink-jet Printer
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INPUT/OUTPUT DEVICES
Computer speech synthesis has been accomplished
through voice synthesizers (also called
voice-output devices or audio-response units).
One approach to speech synthesis is synthesis by
analysis, in which the computer records spoken
sounds and replays them as needed. In the other
approach, called synthesis by rule, the computer
applies linguistic rules to create artificial
speech.
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INPUT/OUTPUT DEVICES
Computer speech synthesis has been accomplished
through voice synthesizers (also called
voice-output devices or audio-response
units). Musical Instrument Digital Interface
(MIDI) is a set of rules designed for recording
and playing back music on digital synthesizers.
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INPUT/OUTPUT DEVICES
A terminal is a device (or combination of
devices) that combines both input and output
capabilities. A dumb terminal consists of a
screen and keyboard and has no processing power
of its own. An intelligent terminal combines a
keyboard and monitor with memory and a processor,
giving it the ability to perform limited
processing functions.
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INPUT/OUTPUT DEVICES
A point-of-sale (POS) terminal is a combination
of input and output devices designed to capture
retail sales data at the point where the
transaction takes place.
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INPUT/OUTPUT DEVICES
Video graphics are a series of computer-produced
pictures that, when displayed in rapid
succession, appear to be in motion. Video-graphic
arcade games are played with a joystick, which
allows fingertip control of figures on the
screen.
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INPUT/OUTPUT DEVICES
In computer-aided design/computer-aided
manufacturing (CAD/CAM), computers are used to
design and manufacture products.
Computer-integrated manufacturing (CIM)
integrates CAD/CAM and the entire manufacturing
process.
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INPUT/OUTPUT DEVICES
A designer using CAD software to design
components.