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3.5 Connecting Audio Input & Output, Bidirectional Audio
Audio Input
The DVR audio inputs adopt BNC port. Device supports bidirectional talk via BNC.
Due to high impedance of audio input, 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.
Audio Output
The audio output signal parameter is usually over 200mv 1KΩ (BNC). It can be directly connected 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.
