A glossary of data-video terms,and how they relate to Dukane's products.
Bill McIntosh
Authorized Dukane Consultant
Phone :843-442-8888
Email :WKMcIntosh@Comcast.net
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Understanding the terms used to describe any technology can be a daunting task.
Those who create technology have a tendency to use terms with the assumption that
they are self-explanatory. Of course, that is not always the case, and the terminology
used to describe data-video projector can also be as difficult to comprehend as those
used to describe computer technology.
Here is a glossary of the most commonly used terms used to describe the features and
functions of a data video projector, and how they apply to Dukane data-video
projectors.
A
AC Port: The AC port on a projector is simply another name for the port where he
electricity (Alternating Current) comes into the projector. All Dukane projectors use the
most widely used power cable, shown below
The fact that all Dukane projectors used this cable is fairly significant. Some projector
manufacturers have chosen NOT to use these standard cables, which are the same
power cables used on most PCs and many other devices. Most tech /IT offices have
dozens of these cables, and a replacement cable of this type can also easily be found
in most local stores. Buying or borrowing a power cable can easily fix the dilemma of
leaving behind or misplacing the power cable. However, locating a special power cable
for a particular projector that doesn't used this standard cable is often a problem.
2. ANSI-American National Standards Institute. A group that creates what are meant to
be agreed-upon standards for technology. In terms of projectors, ANSI is most often
used for two terms predictive of the quality of a projected image, ANSI Contrast and
ANSI lumens.
ANSI Contrast: Contrast is the ratio between white and black. The larger the contrast
ratio the greater the ability of a projector to show subtle color details and tolerate
extraneous room light.
ANSI Lumens: A standard for measuring light output, used for comparing projectors.
.
Aspect Ratio: The most popular aspect ratio is 4:3 (4 by 3). Early television and
computer video formats are in a 4:3 aspect ratio, which means that the width of the
image is 4/3 times the height.
Examples: A 15 inch monitor is 12 inches wide by 9 inches high (9 x 4/3 = 12). A
resolution of 640x480 is a 4:3 format (480 x 4/3 = 640). Other formats are 5:4 used by
the 1280x1024 SXGA resolution, 16:9 is used by HDTV, and 3:2 for 35mm slides
Many movies are designed to be shown in he 16:9 ratio .
ATA Rated Case: A case rated strong enough to be shipped by common carrier;
freight lines, UPS, FedEx, etc. Most cases of this type are easily recognized by their
metal reinforced corners and handles.
.
B
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Back Room Projector: A projector with a "long-throw" lens designed to be used from
the far back of the room, often in a projection booth, balcony, or back of an auditorium.
Many projectors have lenses available for "long-throw" applications.
C
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Component Video: Component Video is a method of delivering quality video (RGB) in
a format that contains all the components of the original image. These components are
referred to as luma and chroma and are defined as Y'Pb'Pr' for analog component and
3. Y'Cb'Cr' for digital component. Component video is available on some DVD players
and projectors. The cable for component video is typically that with red, green and blue
RCA tips.
Composite video –With composite video, the entire video signal is transmitted on one
cable. Composite cables are typically color-coded yellow( the video cable) white and
red( the audio cables). This is the lowest quality means to send video to a projector,
but still remains a common standard particularly on older VCRS, and DVD players
where HDMI ( the highest quality) is not an option. These cable also have RCA tips.
Contrast Ratio: The ratio between white and black. The larger the contrast ratio the
greater the ability of a projector to show subtle color details and tolerate extraneous
room light. A higher contrast ratio means a crisper image.
D
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Diagonal Screen: A method of measuring the size of a screen or a projected image. It
measures from one corner to the opposite corner. A 9FT high, 12FT wide, screen has
a diagonal of 15FT. It is typically assumed that the diagonal dimensions are for the
traditional 4:3 ratio of a computer image as per the example above. Some screens are
square, others particularly wide for 35mm slides 3:2 ratio. As such even if the screen is
12x12, we would rate it 15FT diagonal since that would be the diagonal of the usable
area. OK, how about this! Remember high school? Here's your old geometry lesson. X-
squared times Y-squared equals Z-squared. 3ft by 4ft screen = 3 squared (9), + 4
squared (16), equals 25 (5 squared) a 5 ft diagonal image.
Digital Light Processing (DLP): The commercial name for this technology from Texas
Instruments (TI): The technology inside is often referred to as either "micro-mirrors", or
DMD: The most amazing part of DLP micro mirrors, is the scale of size. The hinges
and motors are packed onto a "wafer" a bit larger than your thumbnail.
Distribution Amplifier: An amplifier used to maintain a clean noise free signal to the
projector over significant distances. Even with good heavily shielded cables, range of
video and computer signals is limited to a few dozen feet before noticeable
degradation. In ceiling mount situations, where the wiring may pass along side or
across electrical conduits, etc. a distribution amp may be needed with shorter
distances. Many distribution amps can also split the signal into 2 or more amplified
signals for driving multiple projectors, projectors and monitors. A common error is using
a cable too long for a strong signal to reach the projector. The need for a “DA” varies
with the quality of the cable, but using a cable much longer than 25 feet generally calls
for a distribution amplifier.
4. DVI: DVI means Digital Visual Interface. DVI is a standard that defines the digital
interface between digital devices such as projectors and personal computers. For
devices that support DVI, a digital-to-digital connection can be made that eliminates
the conversion to analog and thereby delivers an unblemished image. DVI was an
early digital interface. HDMI is largely taking the place of DVI.
F
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Focal Length: The distance from the surface of a lens to its focal point.
Form Factor: A general description a major feature or features that identify a type of
projector or category of capabilities. Projectors with a smaller form factor are more
portable. However, a smaller form factor also allows for fewer inputs and a smaller fan
and room for heat to dissipate. A smaller form factor is ideal for a traveling presenter or
“road warrior. A slightly larger form factor for a classroom or conference room remains
portable, but does not limit inputs or the size of the case. Projectors used for a
permanently fixed in stallion can have a larger form factor, since they will seldom if
ever be used. Again, a common error is to assume that a very small affordable
projector will suffice for all day classroom or conference room use.
Front Room Projector or Position: A unit that sits close to the screen, its short throw
lens projects an image size that is about the same as the distance to the screen. 6FT
diag. screen = 6FT distance. Generally the unit might be as close as 3/4 the screen
size or as far as 1.2 times image size.
H
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Halogen Lamps: Used in most low and medium priced projectors, these lamps last
about 40 hours, with consistent output throughout their life. Although halogens look
very white compared to a normal incandescent lamp, they are not as white as metal
halide units. Cost of operation: Under $0.50 per hour. Most projectors using halogen
lamps carry a spare lamp inside. Halogen lamps were used in early projectors and may
be in some “legacy projectors, but are no longer widely sold.
Hard Wired Remote: Generally a remote control is wireless, and uses infrared
transmitter. There are situations where this is not practical: Large rooms where the
speaker is 35 ft or more from the projector. Rear projection, where the screen will pass
some signal, but normally has the presenter pretty much tied down. Also, the presenter
has to point the remote "at" the projector, which often means turning away from the
audience. A hard-wired remote is generally used where the presenter cannot aim the
5. remote in the direction of the projector, such as a projector mounted in a projection
booth.
HDMI (High-Definition Multimedia Interface) is a compact audio/video interface for
transferring uncompressed video data and compressed/uncompressed digital audio data from
an HDMI-compliant device ("the source device") to a compatible digital audio device,
computer monitor, video projector, or digital television. HDMI is a digital replacement for
existing analog video standards. All of the current models of Dukane projectors have an HDMI
input, in addition to the standard RGB inputs, which makes them ready for use with devices
that can connect via HDMI, including some computers, DVD and Blu ray players and Ipads
(with the Apple HDMI adapter) .
High Gain Screen: A screen that uses one of many methods to collect light and reflect
it back to the audience, which dramatically increase the brightness of the image over a
white wall or semi-matte screen. Technologies used include curved screens, special
metal foil screens (some polarized), and certain glass bead screens. Screens with a
matte-white surface offer less gain, but are the most commonly used screens in
classrooms and conference rooms since they are more affordable and can be cleaned
when needed.
I
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Infrared Remote: The traditional remote control, it transmits infrared, like a television
remote. Typical range is limited to 30 or 35 feet. Infrared requires line of site or a
bounce off of a hard surface. The presenter must pay attention to where the remote is
pointed. Some projectors have an IR sensor in both the front and rear of the projector,
which can help a bit. When working at or near the maximum distance pointing right at
the receiver is necessary. Remember "line of sight" - a person's head, directly between
your remote and the projector may be enough to render it unusable. Radio frequency
remote mousing systems, by comparison, have two distinct advantages, no line of
sight requirement, and longer range. A wireless tablet/slate gives the advantage of
controlling the mouse functions and also is easier to use to simply advance slides or
close or open computer windows .
6. International Power Supply: A unit that can operate under a international selection of
power requirements. The specs of units vary widely, but the minimum is 105-230 volts,
and 50-60 cycles AC (alternating current). If you see a specification like 110v, 220v
instead of a range, those ratings are usually +/- a given percent such as 10%. Some
units are "self-switching" they will automatically switch to whatever power source you
plug it into. Others will have to be switched (internally or externally to accommodate a
difference volt age or cycle range. If your projector comes with some “strange looking”
power cables, those are ones for international use.
Invert Image: Invert image flips the image from top to bottom, to compensate for
ceiling mounting a projector upside down. Projectors typically ceiling-mount upside
down, because most have "keystone" correction built in to compensate for the
distortion created by "pointing up" from the table to the screen. Usual positioning has
the projector about even with the bottom of the screen in a "table top position," or, even
with the top of the screen when ceiling mounted.
K
Kensington Lock Port : Kensington is the brand name of company that produces
security cables and locks for computers and projector. The port to use with a
Kensington lock has become a “defacto” standard. Many Dukane projectors include a
slot for a Kensington security device.
Keystone Correction: Using optics design or other methods to apply a "negative"
keystone to the image, which will partially cancel the effects of keystoning. If you aim a
projector with keystone correction at a screen with the lens level with the middle of the
screen, you will not that the image at the bottom is wider than at the top. When the
projector is in normal position, pointing upward 10-25 degrees, the resulting image is
fairly rectangular.
Keystoning: Keystoning is caused when the projected image is not perpendicular to
the screen, making the top and bottom of the image different lengths. The keystone
effect, and the need for keystone correction can be avoided by simply placing the
projector at a point as perpendicular at possible to the screen. They keystone
correction feature offered in many projectors helps to assure of a rectangular image.
L
LAN-Local Area Network: Some projectors now come with an input so the projector
can be put on a LAN. There are two reasons to have your projector on a lan. Using
software, a site or IT administrator can check the status of the projector monitoring
7. such things as the lamp life on the projector and whether it is on or off. Some
projectors now come with software that allows an image to be wireless projected over a
LAN as well
Laser Pointer: A small pen or cigar-sized pointer, that contains a small battery
powered laser, which can project a small, red (typically), high intensity beam of light
that is immediately very visible on the screen. Excellent for pointing to objects or text,
to make a point. Some schools have avoided or even banned the use of laser pointers
simply because of the risk of them being used by incorrectly or picked up b students
and aimed at someone’s eyes.
LCD: LCD stands for liquid crystal display and comes in many forms, sizes, and
resolutions. Its primary purpose is to present a digital image for viewing. A common
use of LCDs is as a display on a notebook computer and “smart phones
Lens Shift: The Lens Shift feature of a projector allows the optical lens to be physically
shifted up and down (Vertical) or left and right (Horizontal). Most all lens shift
mechanisms are motorized with vertical lens shift being the most popular. With a
projector that has lens shift you can optically correct for keystone distorted images. It is
also used to help geometrically align images when stacking projectors.
Long Throw Lens: A lens designed for projection from the back of a room, or rather
the back of a long room. Long throw lenses would be used a projection booth in the
back of a theater, a church, or a large ballroom in a hotel or other venue. A typical long
throw lens might have to be 50 to 100 FT back to project a 10FT diagonal image.
Some long throw lens is “factory installed”. Some projectors include what is typically
called a “bayonet mount” where different lens can be added, just as a bayonet can be
added to, or left off of, some rifles as needed.
M
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Maximum Image Size: The largest image a projector can throw in a darkened room.
This is usually limited by focal range of the optics.
Menu Driven: Refers to the type of controls on a projector. A typical menu driven
system, will first offer a menu of major categories such as Computer, Video, Audio,
Display, Options. After selecting Computer, you will get another menu of choices with
items like brightness, contrast, number of colors, color balance, sync. Select one of
those and you can then adjust it. Many projectors, which are menu driven, also offer
the most widely used functions in a non-menu fashion, such as have separate buttons
on the remote for volume, brightness, and contrast, as well as switching between
channels/sources. One factor to look for is if the projectors menus can be adjusted
WITHOU a remote. There are two kinds of projector remotes: those that will soon be
8. misplaced and those that are misplaced. Of course a celling mounted, fixed projector
should be mounted so that the menus don't need to be adjusted, but it is good to know
whether the menus can be controlled on the projector without a remote. Most
projectors DO have “redundant menus” on both the remote and the unit itself. Some
don't.
Metal Halide Lamp: The type of lamp used in most current projectors. These lamps
typically have a "half-life" of 2000-6000 hours. That is they slowly lose intensity
(brightness) as they are used, and at the "half-life" point, they are half as bright as
when new, but typically don't suddenly fail these lamps output a very "hot" temperature
light, similar to mercury vapor lamps used in streetlights.
Smaller “road warrior projectors”, the less than 5 lb. category, have a smaller form
factor and thus a smaller fan. While these are being used in classrooms and
conference rooms, they were not designed or meant to be “always on” for several
hours.
Mini Plug: Since most laptop, and many desktop computers, has a headphone port,
this port can be used to send the sound from a computer to a projector.
A male-to-male mini plug cable, using the tip shown below can be used to accomplish
that, if the projector has a mini plug in. Likewise a projector may have an audio-out port
that uses the kind of mini-pin connection, so that a set of speakers can be attached to
the projector.
Minimum Distance: The closest position that a projector can focus an image onto a
screen.
9. NTSC: The United States broadcast standard for video and broadcasting. A VCR has
NTSC output. PAL is a European standard
O
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OHP: The common abbreviation for overhead projector.
Overhead Projector (OHP): A device consisting of a light source, a transmissive or
reflective platform, and a focusable lens assembly. An OHP is designed to project
images from transparencies onto a screen. With the advent of affordable visual
presenters and document cameras, OHPs are not the classroom staple they once
were. However, they do represent a tool that does what is was mean to do. It is also
possible to get inkjet compatible transparencies, and make good transparencies where
an OHP is available to use.
P
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PAL: A European and international broadcast standard for video and broadcasting.
Higher resolution than NTSC.
Panel: Also known as a projection panel, LCD projection panel, or plate. The panel is
the predecessor of today's projectors. They worked with an overhead projector. Most of
these are “retired” from use.
Power Zoom : A zoom lens with the zoom in and out controlled by a motor, usually
adjusted from the projector's control panel and also the remote control.
Projector: A projector is a device that integrates a light source, optics system,
electronics and display(s) for the purpose of projecting an image from a computer or
video device onto a wall or screen for large image viewing. There are hundreds of
products available in the market and their resolution, performance features, warranty
and support differentiate them. These devices attached to a computer or video
devices, as you would connect a monitor. A “data-video “ projector is a more accurate
term as it suggests the fact that these can be used to project the Image from a
computer or a video source, such as a Video camera, VCR, DVD player or blu ray
player .
10. R
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Rear Screen Projection: Using an opaque screen, the projector is placed behind the
screen, invisible to the audience. It projects onto the screen and the audience sees it
on the other side. Good rear projection screens actually produce brighter images than
some standard screens. So as not to waste space behind the screen, ideally a
projector with a short throw lens is used. Since the projector can be placed even with
the middle of the screen, without blocking anyone's view, keystoning is not a problem.
RCA cable –An RCA cable uses the plug seen below . Both composite(Red Green,
Blue) and Component ( Yellow, white and red) use RCA cables, which make it easy to
confuse them. Also, some projectors have a pair and Red and White RCA ports, which
can be used for “audio out” to a set of speakers.
Reverse Image: Reverse image is a feature found on most projectors, which flips the
image horizontally. When used in a normal forward projection environment text,
graphics, etc, are backwards. Reverse image is used for rear projection.
RGB: Red, Green, Blue; the normal type of monitor used with computers, examples of
usage: RGB input or output often referred to as Computer input or output.
RS-232 Port : An RS-232 Port is a serial connection found on the input section of
many projectors. Its typical use is for the addition of a wired remote as described here
in the glossary. It has “male “ pins and is easy to confuse with
11. S
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S-Video: A video transmission standard that uses a 4-pin mini-DIN connector to send
video information on two signal wires called luminance (brightness, Y) and
chrominance (color, C)
SECAM: A French and international broadcast standard for video and broadcasting.
Higher resolution than NTSC.
Short Throw Lens: A lens designed to project the largest possible image from short
distance. Most front room projectors use short throw lens. They are often required for
rear projection, where the depth behind the screen is limited. A typical short throw lens
might produce a diagonal image size of 10 FT, from a distance of 7 to 10 FT.
SVGA: SVGA is used to define a specific display resolution. Resolution is defined by
the number of individual dots that a display uses to create an image. These dots are
called pixels. An SVGA display has 800 horizontal pixels and 600 vertical pixels giving
a total display resolution of 480,000 individual pixels that are used to compose the
image delivered by a projector.
SXGA: SXGA is used to define a specific display resolution. Resolution is defined by
the number of individual dots that a display uses to create an image. These dots are
called pixels. An SXGA display has 1280 horizontal pixels and 1024 vertical pixels
giving a total display resolution of 1,310,720 individual pixels that are used to compose
the image delivered by a projector.
T
Throw Distance : Throw distance is a term used to explain how far the image can be
“thrown” from the computer to the screen. Put another way, if you have an existing
screen size, the throw distance will determine how fan away from the screen the
computer should be placed for the best image. Throw distance falls in one of four
categories. Long throw, Standard throw, short throw , and ultra-short throw.
12. Since most classrooms are 12” from floor to ceiling , the typical screen sizes are 6”x6”,
8’x8’ or 10’x10’. Larger rooms or larger presentation areas can of course support larger
screens.
Dukane makes the process of determining the throw distance easy with this very useful
Prjojection distance calculation webpage:
http://www.dukane.com/av/products/ProjectorCalculator.asp?
Every current Dukane model is listed, as well as “historic models” ( no longer sold but
still in use) . It also suggests a location based on ambient light in the room. This chart
makes it much easier to chose the right projector for your needs, and to know where to
place if for the best results.
Here is a another way to look at this. The location of a standard throw projector should
be roughly twice the width of the screen. If you walk into a room and look at the
existing screen, you can estimate how far away from the screen a standard throw
Projector using the formula L ( location) = SW( screen width) X 2.
Example: Given a 6 foot screen a standard throw projector would be 12 feet away from
the screen
A short throw projector could be 9 feet away from the screen
An ultra short throw projector could be three feet away from the screen.
And a long throw projector could be at the back of the room, 25 feet away.
These are rough distances used for the sake of example. The projector calculator on
the Dukane website takes away any guesswork. Most projectors include a throw
distance chart either on the data sheet or the user manual.
A zoom lens adds a plus/minus variable . Meaning you can make the image slightly
larger or smaller. Ideally you want to zoom in the projector as much as possible,since
that also means the light is more focused and less difused, resulting in a a brighter and
sharper image from a given distance.
13. U
Ultra short throw projector : A category of projectors designed to be set up and used
only a few feet from the screen or projection surface. These projectors are widely used
with interactive whiteboard or in the case of a rear projection screen.
USB-Universal Serial Bus- USB is another term for a standard on computers and
related technology devices like Data video projector. The USB port on a Projector can
be used either to connect the projector to the computer in some cases. USB ports on
projectors can also be used to allow “computer-less “presenting if the presentation is
put on a USB “Flash drive”
UXGA: UXGA is used to define a specific display resolution. Resolution is defined by
the number of individual dots that a display uses to create an image. These dots are
called pixels. A UXGA display has 1600 horizontal pixels and 1200 vertical pixels
giving a total display resolution of 1,920,000 individual pixels that are used to compose
the image delivered by a projector
V
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VGA: VGA is used to define a specific display resolution. Resolution is defined by the
number of individual dots that a display uses to create an image. These dots are called
pixels. A VGA display has 640 horizontal pixels and 480 vertical pixels giving a total
display resolution of 307,200 individual pixels that are used to compose the image
delivered by a projector. Virtually all computers today produce an image greater than
VGA. At one time many projectors were only capable of VGA resolution.
VGA Cable: The VGA cable is a 15 pin male-to-male cable. It remains the most
common way to attach a computer to a projector. This same cable is used on many
PCs to connect the video card on the computer to a monitor. This is also sometimes
called an RGB cable, and some projectors show the port where this cable is to be
plugged as the “RGB “ port instead of the “Computer “port.
14. VGA-Out (also called Monitor out). : Many projector have a port that allows the
signal coming INTO the projector from a computer to be “split” and shared with a PC
monitor. This feature is useful, for example , where the PC is at a desk and what is
being presented is showing up behind the desk. When a monitor is attached to the
projector, the presenter gets a “mirror image” of what is being presented to the
audience.
W
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WSXGA: WSXGA defines a class of SXGA displays with a width resolution sufficient to
create an aspect ratio of 16:9. Resolution is defined by the number of individual dots
that a display uses to create an image. These dots are called pixels. A WSXGA display
has 1920 to 1600 horizontal pixels and 1080 to 900 vertical pixels respectively that are
used to compose the image delivered by the projector.
WXGA: WXGA defines a class of XGA displays with a width resolution sufficient to
create an aspect ratio of 16:9. Resolution is defined by the number of individual dots
that a display uses to create an image. These dots are called pixels. A WXGA display
has 1366 to 1280 horizontal pixels and 768 to 720 vertical pixels respectively that are
used to compose the image delivered by the projector.
X
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XGA: XGA is used to define a specific display resolution. Resolution is defined by the
number of individual dots that a display uses to create an image. These dots are called
pixels. An XGA display has 1020 horizontal pixels and 768 vertical pixels giving a total
display resolution of 783,360 individual pixels that are used to compose the image
delivered by a projector. Most, if not all projectors today, have minimum resolution of
XGA.
15. Z
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Zoom Lens: A lens with a variable focal length providing the ability to adjust the size of
the image on a screen by adjusting the zoom lens, instead of having to move the
projector closer or further.
Zoom Lens Ratio: Is the ratio between the smallest and largest image a lens can
projector from a fixed distance. For example, a 1.4:1 zoom lens ratio means that a 10
foot image without zoom would be a 14 foot image with full zoom. Conversely, a 10
foot diagonal image at 15 feet with no zoom would still be a 10 image at 21 feet at
maximum zoom (15 x 1.4 = 21 feet). A zoom lens is "not as bright" as a fixed lens, and
the higher the ratio, the less light output. As anyone knows who has shined a flashlight
on a nearby wall , and then on a wall several feet away, light disperses over distance.
However, without a zoom lens , some projectors would not FIT on the available screen
where it not possible to place the projector as close to the screen as might produce a
brighter image.
Here is how these terms apply to a typical Dukane projector
The Data sheet on the Dukane 8928A can be found here :
http://www.dukane.com/av/products/documents/specs/8928A.pdf
16. Here is a picture of the 8928A
While it has a low profile form factor, you can also see it has a good-sized air filter port
on the right to keep the unit cool.
The product sheet lists this as a 2700 ANSI Lumen Unit, bright enough for almost any
classroom
The 4000:1 Contrast ratio means it will produce a very crisp image.
17. This diagram of the input area on the 8928 A will show many of the glossary terms in
use
“Crestron” is the name of company well known for software to control projectors at
large scale installations. The fact this unit is “Crestron Ready” simply acknowledges
that fact to those who already use Creston’s products.
Finally, there is one term that probably doesn't need explanation in a glossary but does
need to be pointed out in terms of how it applies to Dukane’s products:
Warranty
Dukane offers FIVE year warranty on most of its projectors. Most other carry either a two or
three year warranty. Since a one year extension of a warranty can cost as much as $400, there
is added value in each Dukane projector.
18. The full line of Dukane products can be found here :
www.dukane.com/av
Bill McIntosh
SchoolVision Inc.
Authorized Dukane Consultant
Phone :843-442-8888
Email :WKMcIntosh@Comcast.net
Twitter : @OtisTMcIntosh
SchoolVision Website on Facebook: https://www.facebook.com/WKMIII