29SN Name SN Name1 Alarm input/alarm output 2 HDMI port（Reserved port. Right nowsystem does not support HD decodecard.）3 Power port 4 HDMI port5 eSATA port 6 USB port7 SAS port 8 Video VGA output9 Network port 10 RS485 port11 RS232 port 12 Audio input port13 Audio output port2.3 Alarm ConnectionPlease refer to the following sheet for alarm input and output connection.There are two alarm input types for you to select: normal open (NO) and normal close (NC).1. Alarm inputa. Please make sure alarm input mode is grounding alarm input.b. Grounding signal is needed for alarm input.c. Alarm input needs the low level voltage signal.d. Alarm input mode can be either NC (normal Open) or NO (Normal Close)e. When you are connecting two NVRs or you are connecting one NVR and one other device, please usea relay to separate them.2. Alarm outputThe alarm output port should not be connected to high power load directly (It shall be less than 1A) toavoid high current which may result in relay damage. Please use the co contactor to realize theconnection between the alarm output port and the load.3. Please make sure the front-end device has soundly earthed.Improper grounding may result in chip damage.2.3.1 Alarm input and output details2.3.1.1 DNA 3U NVR /DNA 4K 3U/DNA 4K S2 3U SeriesUser may refer to the following sheet X for alarm input and output information. See Figure 2-20.
