P9
2.6.4 Audio signal output
Commonly the output parameter of DVR audio signal is greater than 200mv 1KΩ(RCA) which can
connect the low impedance earphone and active sound box or other audio output equipments through
power amplifier. If the sound box and the tone arm can not be isolated, howling phenomena is often
existed. There are some methods to deal with the above phenomena.
1、 Adopt better directional tone arm.
2、 Adjust the sound box volume to be under the threshold that produces the howling phenomena.
3、 Use fitment materials that absorb the sound to reduce reflection of the sound.
4、 Adjust the layout of the sound box and the tone arm.
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. The shielded twisted pair is recommended.
B. Avoid the entrance of high voltage. Make the layout reasonably. Take precaution from the
thunder.
C. In the outlying end connect 120Ω resistance paralleled to reduce the inflection and insure the
signal quality.
D. The 485 AB lines of DVR can not connected with other 485 output equipments paralleled.
E. The voltage between the AB lines of the decoder must be less than 5V.
3 Basic operation
Note: The button in gray display indicates nonsupport.
3.1 Turn on
Plug the power supply and turn on the power supply switch. Power supply indicator light shining
indicates turning on the video recorder. After the startup you will hear a beep. The default setting of video
output is multiple-window output mode. If the startup time is within the video setting time, the timing video
recording function will start up automatically. Then the video indicator light of corresponding channel is
