Appendix; Appendix 1：Lightning And Surge Protection; Appendix 2：Rs485 General Knowledge - jetek pro jts-322dn User Manual

Appendix

Appendix 1：Lightning and surge protection
The outdoor speed dome need to have the function of lightning and surge protection, so that to
make sure the electronic component is safe, you can take the following measures：
The transmission cable must be keep 50 meters away from the high-tension apparatus and
high-voltage cable；
It's better to arrange the outside cable under the eave;
In the open area, the wire must be sealed by the steel tube, and connect the earth by one end,
the way of overhead wire arrangement is forbiddened；
In the strong lightening storm or high voltage areas, the extra high-power lightening
protection device and lightning rod are needed.
The design of lightning protection must be matched with the building's lightning protection
requirement and it needs to correspond the country and industry standard's requirement.
The system must connect the earth at iso-electric level. The earth connection device must
meet the requirement of anti-interference and electrical safety and can't be short circuit or
hybrid junction with the strong current. When the system connect the earth, the resistance is
no more than 4Ω, the cross sectional area is no less than 25mm
Video Lightning arrester; Communication Lightning arrester; Power Lightning arrester; Earth
conductor's resistance is no more than 4Ω; Steel jacket; Lightning arrester; Speed dome must
installed under the lightning arrester within 45 degrees.
Appendix 2：RS485 General Knowledge
1. RS485 Basic Features
According to the RS485 industry standard, the resistance is 120Ω, the maximal load capacity
is 32 valid load.
2. RS485 transmission distance
When using the FTP of 0.56mm(24AWG) as cable, according to the baud rate's difference,
the maximal transmission distance is as following:
Baud Rate Max. Distance
2400Bps 1800m
4800Bps 1200m
9600Bps 800m
39
2.