Alarm Input Port - Dahua NVR21-S2 Series User Manual

1～16
NO1 C1, NO2 C2, NO3 C3, NO4
C4
NO5 C5 NC5
CTRL 12V
＋12V
A/B
Note

Different models support different alarm input ports. Please refer to the specifications sheet for
detailed information.

Slight difference may be found on the alarm port layout.

2.3.2 Alarm input port

Connect the positive end (+) of the alarm input device to the alarm input port (ALARM IN 1～16) of the
NVR. Connect the negative end (-) of the alarm input device to the ground end (
Note

There are two alarm input types: NO/NC.

When connect the ground port of the alarm device to the NVR, you can use any of the GND ports
ALARM1～ALARM16. The alarm becomes activated in the
low level.
Four NO activation output groups. (On-off button).
One NO/NC activation output group. (On-off button).
Control power output. Disable power output when alarm is
canceled. Current is 500mA.
Rated current output. Current is 500mA.
GND
485 communication port. They are used to control devices
such as PTZ. Please parallel connect 120TΩ between A/B
cables if there are too many PTZ decoders.
Figure 2-66
) of the NVR.
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