Dahua NVRPRO User Manual page 18

Port Name
1-3-ch alarm
NO1 NO3
output port
C1 C3
A RS485
communication
port
B
Power port
Power button
Connection Function
3 groups of alarm output ports. (Group 1
port NO1 C1,Group 2:port NO2
C2,Group 3:port NO3 C3 ).Output alarm
signal to the alarm device. Please make
sure there is power to the external alarm
device.
NO Normal open alarm output port.
C Alarm output public end.
RS485_A port. It is the cable A. You can
connect to the control devices such as speed
dome PTZ.
RS485_B.It is the cable B. You can connect to
the control devices such as speed dome PTZ.
Input 12V DC.
Power on/off button.
18