20
Alarm Input
The alarm input port supports alarm signal from ground and device of 12V-24V voltage.
If the alarm device is connected to the Device and other devices, use relay for isolation.
Alarm Output
The alarm output port cannot be connected to high-power load (less than 1A). When constructing
the output circuit, the excessive current should be prevented from causing damage to the relay. Use
the contactor for isolation when applying high-power loads.
PTZ Decoder Connection
The common-ground must be prepared for PTZ decoder and the Device; otherwise the
common-mode voltage might not be able to control the PTZ. It is recommended to use
shielded twisted pair, and the shielding layer can be used for common ground.
Prevent interference from high-voltage power, make reasonable wiring, and take measures for
lighting protection.
Parallel connect 120Ω resistance to reduce reflection and ensure high signal quality.
The Device RS-485 A line and B line cannot connect to other RS-485 output device in parallel.
The voltage between the A line and B line must be less than 5V.
Front-end Device Grounding
The bad grounding might result in chip damage.
No restriction for types of alarm input
The alarm input can be Always On or Always Closed.
2.5.1
Alarm Input Type
Describes alarm input and output ports.
Alarm input/output port
Table 2-4
Alarm input/output port Description
