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Video skew adjustment (AS and AUS models only)
The category 5, 5e and 6 cabling supported by the modules consists of four pairs
of wires per cable. Three of these pairs are used to convey red, green and blue
video signals to the remote video monitor. Due to the slight difference in twist rate
between these three pairs, the red, green
and blue video signals may not arrive at
precisely the same time. This is visible as
separate colour shadows on high contrast
screen images and is particularly apparent
when using higher screen resolutions and
some types of category 5e cables.
To alleviate this situation, the CX Remote
AS and AUS modules provide internal
skew adjustment that can help to rectify
the situation. The skew adjustment works
by delaying or advancing the timing of any
of the red, green or blue colour signals so
that they are all delivered to the monitor
at precisely the same time. For best results,
the “skew” program supplied on the disk or available from Black Box technical
support is the most accurate way of setting skew as the red, green and blue
lines are rendered exactly on the screen as single pixel wide lines. The skew.bmp
test pattern can also be used but it is less accurate. Alternatively, you can create
your own skew pattern using a standard image creation package, as detailed
opposite.
Convergence test
pattern showing the
RGB crosses. In this
case, the green signal
can be seen out of
line with the other
two colours.
1 2 3 4 5 6 7 8
8
6
5
2
8
6
5
2
Data signal
Red
video signal
Green
video signal
Blue
video signal
7
3
4
1
7
3
4
1
To use skew adjustment
1 Display a skew pattern on the appropriate computer. You can either use the
supplied skew pattern or create your own:
Using the supplied skew pattern
i Insert the supplied Installation CD-ROM into the CD player of the computer.
ii Within Windows, use the
My Computer
option (usually available as a desktop icon
or within the Start menu) to view the
contents of the CD-ROM. Double-click
the
Skew
entry to display the standard
test pattern. If necessary, maximise the
application window so that the image fills
the screen.
The screen will show a series of fine red,
green and blue crosses which should all
be in line, vertically and horizontally. Skew
affects the horizontal placement of the colours and using this pattern it is
much easier to discover which, if any, colours are being adversely affected by
the cable link.
Creating a skew test pattern
skew test pattern
i Run any image creation/editing application, such as the Paint program
supplied with Windows.
ii Using the image application create three
stacked horizontal rectangles (one red,
one green and one blue) that fill the
width of the screen.
iii Draw a vertical black line down across
the coloured bars and then repeat this
vertical line at intervals along the width
of the coloured bars. These lines create
breaks across the colours and give you
more opportunities to view the horizontal
position of each colour relative to the others.
2 On the keyboard connected to the ServSwitch CX Remote module,
simultaneously, press the hotkeys (by default,
and
) along with
to
enter configuration mode.
The three keyboard indicators (‘Num Lock’,
‘Caps Lock’ and ‘Scroll Lock’) will now begin
to flash in sequence.
