Advanced Manual

Table Of Contents
3-41
Wiring
Keep strong-electricity cables (for example, power cord) at least 30 cm (11.81 in) away from
weak-electricity cables (for example, network cable and audio/video cables).
Connect the cables correctly. Wrong connection may damage the device. You can attach labels
on the cables for easy identification to avoid wrong connection.
Use the power adapter delivered with the product. Power adapter with poor quality may
damage the device.
Keep away with interference when installing alarm cables to avoid false alarm.
Use T-shape connection when you connect RS-485 serial cables, that is, use one cable as a trunk,
and distribute branches on the trunk. The cable on a trunk should be no more than 15 m (49.21
ft), and the terminating resistance is installed on the farthest camera. If multiple nodes are not
in a straight line, use zigzag-shape connection. Do not use star shape or combination of T shape
and zigzag shape.
Do not lay video cables or RS-485 serial cables on stilts. Take lightning protection measures, for
example, by using an external lightning protection device, when you lay video cables and RS-485
cables outdoors. For more information, see Lightning Protection.
Cable Requirements
Video Cable
The commonly used composite video cables are coaxial cables. A coaxial cable consists of four layers.
This cable has a copper center conductor surrounded by a foam polyethylene dielectric. A bonded
copper braid provides shield coverage and the outermost polyethylene cover provides protection for
the whole cable. The cable structure is shown in Figure 3-1.
Figure 3-1 Coaxial cable
(1) Center conductor
(2) Polyethylene dielectric
(3) Copper braid
(4) Polyethylene cover
A larger section surface of the conductor provides less signal loss during transmission and a longer
transmission distance. The shield coverage prevents the transferred signals from being interfered by
external electromagnetic waves and electrostatic fields.
Coaxial cables include SYV-75-3, SYV-75-5, SYV-75-7, and SYV-75-9. The transmission distance of a
cable depends on the ambient environment where the cable is used. Generally, in an environment
with little electromagnetic interference and if the signal transmission attenuation is no more than
(1)
(2)
(3)
(4)
(1)
(2)
(3)
(4)