Nitek VB31AT - Manual (Page 4)

Installation & Setup
Unshielded Twisted Pair
(Loop Resistance at 750 feet)
AWG 23 24
Loop Resistance 32 Ohms 39 Ohms
Power. Before making any connections be sure that the power source is correct for the camera
being installed and that the length of Category cable is within the maximum specifications al-
lowed for the camera power requirements. If not, sufficient power may not be available at the
camera. NITEK provides a convenient Voltage Drop Calculator at the web address below to
simplify determining the maximum allowable cable distance to send power over category ca-
bling.
http://www.nitek.net/calculator.html
Mounting
The VB31AT can be mounted external to a camera housing by use of the mounting leg, or can
be placed inside the camera housing.
When mounting the VB31AT externally, the placement should be sufficiently close to the cam-
era housing so that the mini-coax and power cables can be conveniently routed into the camera
housing. The mounting leg of the VB31AT can be used to secure the device either with a screw
or wire wrap. The mini-coax plugs onto the BNC camera video input and the White and the
Black power wires connect to the appropriate camera power inputs.
When mounting the VB31AT inside a camera housing a hole of sufficient size must be avail-
able to pass the RJ45 terminated video/power cable through. The cable must be of sufficient
length to be routed back to the power source and video crossover. As with external mounting,
the mini-coax video cable will connect within the housing to the camera video BNC input and the
White and the Black power wires will connect to the appropriate power inputs on the camera.
Hook-Up
In the diagram shown above, two VB31AT devices are used; one at the Head-End (monitor lo-
cation) and the second at the camera location. Voltage is provided (over 2 pairs) from the moni-
tor location, over 750 feet of 4-pair UTP cable to the camera and passed through the VB31AT
devices at each end. Video is sent back to the monitor over a third pair of the UTP cable by
means of the two baluns operating as video transceivers.
Hook-up wiring chart for the RJ45 connectors is shown on the following page.