With projections systems come a variety of cables and connections
which can be a little confusing so here we explain some of the
basics. If you need to discuss anything to a more technical level
we will be pleased to help.
signal inputs to a projector fall into the following groups: computer,
video, audio and control. Computer and video inputs
feed the projector with images while the control can either represent
a computer mouse or tell the projector what to do. Control is
optional, computer or video feed is necessary to generate images.
The most common form of computer input is via Analogue RGB
(Red, Green, Blue), sometimes referred to as VGA or SVGA (Video
Graphics Array or Super VGA). This is generally terminated with
15 pin HD (high density) connections or sometimes BNC connections
as illustrated below.
pin HD male
pin HD female
pin to 5 x BNC
this type of interface the signal is separated into its red, green,
blue, horizontal and vertical components and each is fed down
a dedicated core in the cable. Using high quality cable it is
possible to run up to 30m without noticeable signal loss. For
runs over 30m we recommend the use of a distribution amplifier
or line driver (signal booster).
recently introduced alternative to RGB input is Digital
or DVI (Digital Visual Interface). Not all projectors can
accommodate this and not all computers can output for DVI. The
advantage is a faster data transfer rate and cleaner signal giving
sharper, fast response images. The disadvantage is that distance
is restricted to around 10m unless using boosters/converters.
To complicate matters there are 3 types of DVI; DVI-A (Analogue),
DVI-D (Digital) and DVI-I (Integrated - both Analogue and Digital).
Most projectors and monitors accommodate DVI-I. However, some
video processing equipment requires DVI-D.
Video signal to a projector generally takes one or more of the
following types (in ascending order of quality): Composite, S-video
is the most universal signal type and most peripherals generating
video signal (e.g. VCR, DVD, camcorder) can output in composite
form. Usually terminated with phono (RCA) or BNC connections,
composite signal is a combination of all of the components fed
down a coax cable (RG59U 75Ω
low loss). With good quality cable distances of up to 100m can
be achieved without noticeable signal loss. Improvements can be
made using a line driver (booster).
phono (RCA) connections are usually colour coded yellow. If your
equipment only has Scart out then a Scart adaptor is necessary
to channel the signal via composite.
video + audio
is a step up from composite in quality terms and is generally
found on higher quality versions of the latest equipment (e.g.
VCR, DVD, digital camcorder). S-video separates out red and green
components and by deduction calculates what the blue component
should be. Horizontal and vertical components are fed with the
red and green signals. Connections are 4-pin mini DIN plugs/sockets.
Using high quality cable it is possible to achieve 30m distances
before needing signal boosting.
your equipment only has Scart out you will need a Scart adaptor
that accommodates s-video (provided that your equipment supports
mini DIN plug
mini DIN socket
takes the signal separation a stage further by utilising 3 cables
to channel each of the basic signal 'components'. Most high-end
video equipment will output in component form and by nature this
offers the highest video quality. Connection
is usually by phono (RCA) or BNC's and colour coded red, green
and blue. Scart to RGB/component cables are available but will
only work if your equipment supports RGB/component out.
Most projectors will offer audio support with low power speakers.
These are intended primarily for use in small meeting rooms where
sound quality is not a major requirement. Speakers are usually
1-3 watts output and sound tends to be tinny. For audio support
in a larger environment or for showing video's/DVD's we recommend
feeding directly into your PA system or using active multimedia
Many projectors these days have some form of control system for
the purpose of using the remote control as a computer mouse (useful
for stand up presentations), or for controlling the functionality
of the projector.
the first case, mouse control (if supported) is achieved simply
by connecting the computer's mouse port to the projector's mouse
port using the appropriate cable (serial, USB or PS/2). The remote
control then communicates with the computer via infra red to the
projector and cable to the computer. Remember to point the remote
at the projector, not the computer!
the second case, control is via RS232 (command protocol) and generally
using a serial connection (9-pin D-sub). It is necessary to have
the right software to send RS232 commands if you want to control
the projector from the computer. Signal transmission is limited
in length according to transfer speed but can be increased using
a line driver (booster)
D-sub serial plug
There are an increasing number of projectors now capable of wireless
data transfer and the technology is improving all the time. This
method eliminates the need for extensive wiring (except power)
and is fine for still images and presentations/song display but
has some way to go on video streaming due to the limited bandwidth
available. This is likely to improve.
is possible to achieve wireless video connectivity using a video
signal transmitter system - essentially a transmitter connected
to the source, converting the signal to radio frequency (RF),
sending to a receiver which is directly connected to the projector.
Reliability is good but restricted to around 30m for standard
models or up to 5km with appropriate amplification.
Some manufacturers are introducing networkable projectors which
gives the advantage of being able to display via the projector
from any computer on the network. Wireless networkable projectors
are also being introduced.
PROmotivations can provide all of the above products and advise
on your specific requirements. We offer a full professional installation
service to bring you the best solution according to your requirements