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Glossary
Addressability
The number of horizontal and vertical
picture elements (pels) in the image.
The higher the addressability, the
more detailed the image that can be
displayed on the screen.
(Addressability is sometimes referred
to as resolution).
DDC Display Data Channel. A VESA
Standard enabling ‘Plug and Play’.
Display Mode The way in which the image generated
by the computer is displayed on the
screen. It is defined primarily by refresh
rate and addressability.
DPMS Display Power Management Signalling.
A VESA Standard.
EPA US Environmental Protection Agency,
responsible for the ‘Energy Star’ power
conservation program.
Horizontal
Frequency
The number of horizontal lines drawn
across the screen by an electron beam
in one second. Measured in kHz.
Interlaced An interlaced display mode causes the
electron beam to refresh the screen
image in two passes. One pass scans
the even lines, the next pass scans the
odd lines.
ISO International Organisation for
Standardisation, responsible for the
ISO 9241 (part 3) Standard for
Computer Systems.
Non-Interlaced A non-interlaced display mode causes
the electron beam to refresh the screen
image in one pass.
NUTEK Swedish National Board for Industrial
and Technical Development, involved
in producing power consumption
guidelines.
Refresh Rate The number of times per second the
Frequency screen image is “repainted”.
Measured in Hz. The higher the (non-
interlaced) vertical frequency, the less
the flicker.
Resolution See Addressability.
SVGA Super Video Graphics Array. Video
Modes with 800 x 600 or higher
addressability.
VESA Video Electronics Standards
Association, responsible for defining
display mode, DPMS and DDC
standards.
VGA Video Graphics Array. Video standard
with 640 x 480 addressability.
XGA Extended Graphics Array. Video
standard with 1024 x 768
addressability.
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