Videovox Pro DVR User Manual page 27

Parameter Grounding Alarm
Ground Ground line
Alarm in 1...4 1, 2, ..., 4. Become activated in low voltage,
Relay Output 1,2,3,4: NO and C(Normally Open and Com)
5: NO,C and NC(Normally Open, Com, Normally Closed)
6: Ctrl 12V(This is used for reset the senor)
485 communication port. They are used to control devices
485 A、B
such as PTZ.
This should input an external power input(Less than 1 A).
+12（C）
4-ch grounding alarm inputs. (Normal open or Normal close type)
Please parallel connect COM end and GND end of the alarm detector (Provide
external power to the alarm detector).
Please parallel connect the Ground of the DVR and the ground of the alarm
detector.
Please connect the NC port of the alarm sensor to the DVR alarm input(ALARM)
If you need to reset the touched-off alarm remotely, you can use DVR to supply
controllable 12 V power to the alarm detector such as the smoke detector.
Use the same ground with that of DVR if you use external power to the alarm
device.
Terminal
Screw
Figure 2-6
27