Model URA, URA-SKU, & URA-XT
10
however, for the daisy chain Model (URA-XT), it is important to
set the cable type (23 vs. 24 AWG) that you are using because of
the cumulative nature of the daisy chain.
•
In the adjustment-mode, press and hold the
SEL
button
for at least 3 seconds to enable the WIRE SIZE selection
mode between 23-gauge wire and 24-gauge wire.
•
The
UP
button is used to select 24-gauge wire. The
DOWN
button is used to select 23-gauge wire.
•
To exit the adjustment mode at any time, press the
SEL
button (the unit also has a built-in timeout to exit this
mode).
3.4 Why Skew Adjustment?
UTP cables have 4 twisted pairs inside. The Hall Research UVA/URA
video transmission on UTP uses 3 individual pairs for each color
(Red, Green, & Blue).
Figure 6 - skew mechanism, explained
As shown in the figure above, a characteristic of Category-5/5e/6
cable is that the pairs of wires are twisted at different rates.
Therefore, for a given length of Cat-6 cable the total length of any
particular pair could be longer than other pairs in the same cable.
Since the signals travel along the length of each pair at a fixed speed,
the arrival times of signals will be skewed in a long cable (those that
have to travel farther arrive later and the corresponding color shifts to
the right).
This is seen on the monitor as separation, or lack of convergence in
colors. For example, a vertical white line on the screen may look to
have a red tinge on the left edge and blue tinge on the right edge.
