30
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To use skew adjustment
1 Display a skew pattern on the appropriate server. 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 server.
ii Within Windows, use the My Server
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
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 remote user keyboard (connected to an ServSwitch CX Remote AS/R
extender), 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.
Remote user skew adjustmentThe category 5, 5e and 6 cabling supported by the ServSwitch CX 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 ServSwitch
CX Remote AS/R module provides 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 obtainable from Black Box 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.
12 3 4 5 6 7 8
8
6
5
2
8
6
5
2
Datasignal
Red
videosignal
Green
videosignal
Blue
videosignal
7
3
4
1
7
3
4
1