11
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Video compensation
The Wizard Extender incorporates video compensation circuitry to
maximize the picture quality for any given length of twisted pair cable.
The amount of video compensation required increases proportionally
with the length of cable run that is being used.
The Wizard Extender can automatically correct the video compensation
settings for any length of cable, however in certain circumstances you
may wish to finely adjust and fix the compensation level to suit
personal preferences - this can be done by switching to manual
compensation mode.
To display a suitable high contrast image
The best way to clearly view the effects of compensation is to display a
high contrast image, with vertical edges, on the screen.
• Open a word processor, type the
capital letter ‘H’, or ‘M’ and increase
the point size to 72 or higher. For best
results, the background should be
white and the character should be
black.
• A BLACK shadow on the right of the
character indicates UNDER
compensation.
• A WHITE shadow on the right of the
character indicates OVER
compensation.
To manually adjust the video compensation
1 Change REMOTE switch 4 to the ON position.
2 Press, in unison, 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. The speed of
the sequence indicates the level of
compensation currently applied: the slower
the rate, the less compensation is being
applied.
3 While watching the displayed high contrast screen image, now
adjust the video compensation setting using the following keys:
• Optionally press
to make the circuitry calculate and
apply an automatic compensation level - you can use this as a
starting point for your fine tuning.
• Press
to increase compensation by one fine step,
• Press
to increase compensation by one coarse step,
• Press
to select the neutral setting (no compensation),
• Press
to decrease compensation by one coarse step,
• Press
to decrease compensation by one fine step.
Note: In total there are twenty two fine steps from one end of
the scale to the other. One coarse step jumps roughly five fine
steps.
Note: If the monitor goes blank and switches off (due to
extreme over compensation) press the
key to restore it.
4 When no shadows are visible and the displayed images have crisp
edges, press
to exit configuration mode.
The new compensation setting will be stored, even when power is
removed or if a complete reset is initiated. The setting should not
require further changes, unless the cabling arrangement is altered.
Note: If REMOTE switch 4 is returned to its OFF position, the video
compensation level will be recalculated and set at the next power
on.
If video compensation cannot solve the problem
If automatic and manual compensation is unable to solve the problem,
an additional module called a ‘Skew Compensator’ may be required.
Please see the next section for details.
High contrast
black character
on white
background
White or black
shadow on
right side -
indicates the
need for
compensation
