Glossary » I/O Devices
puck
a hand-held pointing device used in conjunction with an input tablet for precise positioning. A puck may contain crosshairs for aligning the puck position with drawings placed below it.
Read more »qualifier key
a key on the keyboard that modifies the meaning of other keys that are used along with it, e.g. shift, control, alt, and command keys.
Read more »QWERTY keyboard
the standard North American keyboard layout (pronounced KWER-TEE), named for the first 6 letters that appear along the top-left row. Primary alphabetic keys are arranged in three rows as follows:
QWERTYUIOP
ASDFGHJKL;
ZXCVBNM,./
The layout is thought to…
Read more »raster display
the standard technology for computer monitors that display images on a grid of pixels, allowing the computer to light up any individual pixel easily, and enabling color displays by having individual red, green, and blue (RGB) phosphors at each pixel…
Read more »RGB
red-green-blue; a common color model used especially in CRTs which specifies any given color as a combination of 3 brightness values for red, green, and blue elements. While theoretically equivalent to other color models (HSV, HSB, CMYK), the RGB makes…
Read more »screen real estate
the amount of space available on a display for an application to provide output. Typically, the effective use of screen real estate is one of the most difficult design challenges because of the desire to have as much data and…
Read more »screen refresh rate
the frequency at which a monitor can update its display; in CRTs, the rate at which the electron beam repeats its pass over the entire screen to refresh the dimming phosphors. The refresh rate represents the maximum rate at which…
Read more »sensory modality
A communication channel associated with one of the human senses of sound, vision, touch, smell or taste. As used in discussing usability this may imply input to and output from the computer as well as the human user. E.g., the…
Read more »softkey
a key whose label is specified in software, as in ATM machines and mobile phone interfaces.
Read more »stroke recognition
the conversion of pen strokes into text or computer commands. Thus, when someone enters handwriting, a computer can convert it to text. When they express certain gestures, it can be recognized as commands. For instance, a swiping gesture may be…
Read more »tabletop display
a display built into a tabletop. This may be advantageous in helping people to view it from many positions, including sitting and standing, in an environment where they need to be moving around frequently, in enabling multiple people to view…
Read more »tactile interface
a user interface that uses touch for input and/or output, such as a Braille reader.
Read more »tangible user interface
a user interface whose input and/or output are tangible objects that typically directly represent information in the application domain (as opposed to a mouse, which provides abstract, domain-independent input). Examples include interactive plush toys, blocks, and toy cars.
Read more »tapping
an input technique, used especially with pen-based systems. A tap is a rapid touch then withdrawal from the surface. A screen is tapped with a pen or a touchpad is touched by a finger to indicate selection of an item…
Read more »thumbwheel
a spinning wheel usually spun by a thumb and generally located on a keyboard or mouse or on handheld devices (such as handheld radios). It can be used, for instance, to set values or to quickly scroll or move a…
Read more »toggle key
a key on the keyboard that toggles between two modes. The most common is the CAPS LOCK key which causes all letters to appear as capitals when it is activated. Other common toggle keys include NUM LOCK (alternates between the…
Read more »tongue-activated joystick
an input device for users with limited mobility; a tongue-activated joystick is placed in the mouth and manipulated with the tongue. It can be used in conjunction with a blow-suck tube to move a pointer around and make selections.
Read more »touch interactive display
TID; an input device that overlays a screen, or touchscreen, that recognizes where the user touches as input.
Read more »touch tablet
or drawing tablet; a large flat surface that a user can touch with a hand or a pen (or a puck) to control the position of the pointer on the screen. Touch tablets typically work in absolute coordinates, meaning that…
Read more »touchpad
an input device used for moving the pointer on the screen, much like a mouse. A touchpad is like a small touch tablet that uses relative rather than absolute coordinates. They are common on portables because they allow users to…
Read more »touchscreen
a screen that has a touch-sensitive film over it, allowing a user to touch areas of the screen to move the pointer and press buttons, thus allowing a very direct interaction with an image. Touchscreens are most commonly used in…
Read more »trackball
an input device consisting of a ball set into a base that can be spun to move the pointer on the screen, essentially equivalent to a mouse, but having the advantage of being in a fixed location and therefore requiring…
Read more »TTY
teletype; an ancient terminal that displayed all input and output by printing it on a line printer.
Read more »unistroke text input
pen-based input of alphanumeric characters based on an alphabet of gestures that can all be written with a single pen stroke. For instance, uppercase H usually requires at least 3 strokes (two vertical bars and a crossbar), while lowercase h…
Read more »valuator
a general way of referring to any input device or input method for specifying continuous values (as opposed to selecting among a finite set of choices). Typical devices include control dials and levers.
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