Dahua HDCVI series, User Manual

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Keep it away from strong electromagnetic interference devices.
Using TV as video output device is not a reliable substitution method. You also need to
reduce the working hour and control the interference from power supply and other devices.
The low quality TV may result in device damage.
3.6 Connecting Audio Input & Output, Bidirectional Audio
3.6.1 Audio Input
BNC port is adopted for audio input port.
Due to high impedance of audio input, please use active sound pick-up.
Audio transmission is similar to video transmission. Try to avoid interference, dry joint,
loose contact and it shall be away from high tension current.
3.6.2 Audio Output
The audio output signal parameter is usually over
200mv 1KΩ (BNC). It can directly
connect to low impedance earphone, active sound box or amplifier-drive audio output
device.
If the sound box and the pick-up cannot be separated spatially, it is easy to arouse
squeaking. In this case you can adopt the following measures:

Use better sound pick-up with better directing property.

Reduce the volume of the sound box.

Using more sound-absorbing materials in decoration can reduce voice echo and
improve acoustics environment.

Adjust the layout to reduce happening of the squeaking.
3.7 Alarm Input and Output Connection
Please read the followings before connecting.
1. Alarm input
a. Please make sure alarm input mode is grounding alarm input.
b. Grounding signal is needed for alarm input.
c. Alarm input needs the low level voltage signal.
d. Alarm input mode can be either NC (normal Open) or NO (Normal Close)
e. When you are connecting two DVRs or you are connecting one DVR and one other
device, please use a relay to separate them,
2. Alarm output
The alarm output port should not be connected to high power load directly (It shall be less
than 1A) to avoid high current which may result in relay damage. Please use the co
contactor to realize the connection between the alarm output port and the load.
3. How to connect PTZ decoder
a. Ensure the decoder has the same grounding with DVR, otherwise you may not control
the PTZ. Shielded twisted wire is recommended and the shielded layer is used to connect
to the grounding.
b. Avoid high voltage. Ensure proper wiring and some thunder protection measures.