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2.6.3 Audio input
The audio port is an RCA connection.
The input impedance is high so the tone arm must be active.
The audio signal line should be firm and away from any electro magnetic interference and eliminate any poor
joint welding and oxidation. A high voltage current should be avoided especially.
2.6.4 Audio output
The output parameter of the DVR audio signal is greater than 200mv 1KΩ (BNC) which can connect to a low
impedance earphone and active speaker or other audio output equipment through a power amplifier. If the
speaker and the tone arm cannot be isolated, there may be a problem with feedback. There are certain method to
deal with the above issue;
1、 Adopt better directional tone arm.
2、 Adjust the speaker volume to be below the threshold that produces feedback.
3、 Use materials which absorb the sound and reduce sound reflection.
4、 Adjust the location of the speaker box and the tone arm.
2.7 Alarm input and output connections (Only available on certain products.)
１、Alarm input
A. Alarm input is grounding alarm input.
B.
Alarm input demands the grounding voltage signal.
C.
When the alarm is connected with two DVRs or connected with DVR and other equipment, it should be
isolated by relay.
２、Alarm output
Alarm output cannot be connected with a high-power load (no more than 1A).When forming the output loop
it must prevent the big current from relay damage. Use the contact isolator when there is a high-power load
３、PTZ decoder connections
A. The grounding of the PTZ decoder and DVR must be shared otherwise the common-mode voltage will
lead to the PTZ control failure. A shielded twisted pair is recommended.
B. Avoid the input of high voltage, ensure a reasonable layout and take precautions from lightning.
C. In the outlying end connect 120Ω resistance in parallel to reduce inflection and ensure signal quality.
NightWatcher D1 Digital Video Recorder User Manual
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