LIS 505 - Input and output
Machines that feed data into a computer.
Sets of typewriter-like keys
that enable users to enter data and commands
Devices with which users
can control the position of the pointer on the screen.
Pointing devices that users roll around a hard, flat surface.
Mice may be
(containing a ball and mechanical sensors),
(containing a ball and optical sensors),
(using a laser to detect movement).
Mice may connect to computers
via serial ports,
PS/2 mouse ports,
or USB ports.
use infrared or radio waves to communicate with the computer
instead of physical wires.
Pointing devices like upside-down (opto)mechanical mice,
in which users manipulate the ball directly.
Pads over which users move a finger or other object
to control the pointer.
Pointing devices like miniature joysticks,
usually with a rubber tip
and positioned among the keys of a keyboard.
Lever pointing devices.
The more the lever is tilted in any direction,
the faster the pointer moves in that direction.
More precise devices than touchpads,
used for entering drawings.
A tablet has either an electronic stylus (or "pen"),
or a puck (or "cursor")
containing a window with crosshairs.
Also called digitizers, graphics tablets,
touch tablets, or tablets.
Display screens covered with touch-sensitive panels.
Devices that use a light-sensitive detector
to select points on a display screen.
Devices that use a laser to read bar codes
and translate them into digital form.
Devices that perform optical character recognition,
that is, translate images of text from paper
into character code.
Devices that perform magnetic ink character recognition,
by magnetizing characters printed in special ink
and reading the resulting magnetic patterns.
Devices that read printed text or pictures
and translate them into digital form.
Scanners with a flat surface
on which to lay documents to be scanned.
Scanners that feed each sheet of paper
across a nonmoving scan head.
Scanners that are held in the hand
and passed across the image to be scanned.
Cameras that store images digitally.
Devices that change sound into electronic signals.
A sound card usually has a jack
into which a microphone can be plugged.
Symbols that appear on the screen
indicating where input will be applied.
GUIs typically have at least two types of cursor:
(also called the mouse cursor),
which indicates where the next mouse action
(clicking or dragging)
(also called the text cursor or caret),
which indicates where the next character (or other object)
will be inserted in a text.
Recognition of spoken words
either spoken separately (discrete speech)
or in continuous speech.
Also known as speech recognition.
Machines that can present data from a computer.
Devices that produce soft copy,
rather than obvious physical objects such as printouts.
Adapter boards that allow a computer to produce video output
for a monitor.
Also called video cards, video boards,
video display boards, graphics cards,
graphics adapters, and graphics adapter boards.
Devices dedicated to video display,
containing a display screen.
Monitors that use a CRT (cathode ray tube),
in which an electron beam moves across the screen from behind.
Monitors that use liquid crystal display,
in which electric currents cause liquid crystals to align
so that polarized light does, or does not, pass through them.
Nearly all flat-panel displays are LCD.
Color LCDs may be either
which uses thin-film transistor (TFT) technology,
covering several different technologies.
Passive matrix systems are cheaper than active matrix,
but were not perfected as early.
Rate at which a monitor refreshes its display
(which is required for displays,
such as CRTs,
where the contents disappear quickly
if not refreshed).
Normally measured in hertz (Hz) (refreshes per second),
with the standard value being 75 Hz.
vertical frequency, vertical scan rate,
frame rate, vertical refresh rate, or scan rate.
Number of pixels displayed on a screen.
Normally measured as pixels across x pixels down
A monitor cannot display at a higher resolution
than its total number of like-colored dots.
Diagonal distance between like-colored dots on a display screen.
Normally measured in millimeters.
The lower the dot pitch, the sharper the image appears.
Also called phosphor pitch.
Printed circuit boards
that enable a computer to manipulate and output audio signals.
A typical sound card can
generate audio signals from both waveform and MIDI data
and accept input from a microphone.
For users to hear the sounds,
the audio signals must be translated by a device
such as a
Short for musical instrument digital interface.
A standard for controlling devices, such as synthesizers and sound cards,
that play music.
MIDI representations include note pitch, length, and volume,
and sometimes other information.
Devices that produce printouts
or other durable, human-readable records.
Devices that print text or images on paper.
Printers that work by striking something against an inked ribbon.
Impact printers in which pins are struck against the ribbon
to produce patterns of dots on the page.
Printers that do not work by striking against a ribbon.
Printers in which a laser beam alters electrical charges on a drum,
the drum is rolled through toner,
which is picked up by the charged portions of the drum,
and the toner is transferred to paper
through heat and pressure.
Printers that work by spraying ionized ink,
which is directed by magnetized plates.
A paper orientation
in which the page is taller than it is wide.
A paper orientation
in which the page is wider than it is tall.
Short for dots per inch.
A measure of the resolution of a printer.
Short for pages per minute.
A measure of the speed of a printer,
based on printing text.
Production of audio output resembling human speech,
usually from text files.
Also called voice synthesis.
Devices that allow two-way communication between a user and a computer,
typically including a keyboard and a display screen.
Terminals that serve as cash registers
and include other functions
such as recording customer orders, processing credit and debit cards,
connecting to other systems in a network, and managing inventory.
Also called POS terminals.
Last updated October 29, 2002.
This page maintained by
Prof. Tim Craven
E-mail (text/plain only): email@example.com
Faculty of Information and Media Studies
University of Western
Canada, N6A 5B7