VDH-NK800 Hardware Manual
7
The video outputs include VGA and HDMI interfaces.
Pay attention to the following when you select a PC display instead of a
monitor.
1.
Do not remain switched on for a long time to extend the life of the
equipment;
2.
Regular degaussing will help to maintain the normal operation of the
monitor.
3.
Keep away from equipment with strong electromagnetic interference.
Using TV as video output device is an unreliable alternative. It is also
required to minimize the time of use and strictly control the power, the
interference caused by neighboring devices. Leakage risks of low quality TVs
may result in damage to other equipments.
Audio Inputs
Voice input impedance is high, so the microphone must be a microphone
connected to the power supply.
Like video input, voice transmission cables should avoid interference, fake,
poor contact, and special attention to prevent the current of the
high-voltage.
Audio Output
The audio output parameters of NVR are generally greater than 200mv 1KΩ
(BNC), you can directly connect to the low impedance headphones, powered
speakers or other sound devices through a power amplifier.
When the external speakers and microphones can not achieve spatial
segregation, it is prone to the phenomenon of whistling.
You may adopt the following actions,
1.
Using better directional microphones
2.
Adjust the speaker volume to make it lower than the value of the
generated howling.
3.
Using sound-absorbing materials for decoration to reduce sound
reflections and improve the acoustic environment;
4.
Adjusting the layout of the microphone and speakers can reduce the
whistling.
AlarmIn/AlarmOut connections
Pay attention to the following before installation.
1.
AlarmIn
(a)
Alarm input is grounding alarm input
(b)
The alarm input signals require voltage signals to the ground
