Front Panel and Rear Panel 11No. Port Name FunctionAlarminput/output ofNVR4216-16P-IAlarminput port(1-4) They receive signals from external alarm source.Alarm input includes two types; NO (normal open)and NC (normal close). When your alarm input device is using externalpower, make sure the device and the NVR havethe same GND.Alarmoutputport(NO1,C1) One group of alarm output ports (Group 1:NO1-C1). Output alarm signal to the externalalarm device. Make sure power supply isavailable for the external alarm device. NO: Normal open alarm output port. C: Alarm output public end.GND. Alarm input ground port.CTRLControllable 12V power output. It is to control theon-off alarm relay output. It can be used to control thedevice alarm output. At the same time, it can also beused as the power input source of some devices suchas alarm detector.P+12V power output port. It can provide power to someperipheral devices such as camera and alarm device.Make sure the power supply of peripheral device shallbe below 1A.5 HDMI portHigh definition audio and video signal output port. It transmitsuncompressed high definition video and multiple-channel audiodata to displays with HDMI port.6 USB port USB3.0 port. Connect to devices such as mouse, USB storagedevice and USB burner.7 Network port 10M/100M/1000Mbps self-adaptive Ethernet port. Connect to thenetwork cable.8MIC IN Bidirectional talk input port. It is to receive analog audio signal fromdevices such as microphone, sound pickup.MIC OUTAudio output port. It is to output analog audio signal to devicessuch as sound box. Bidirectional talk output. Audio output on 1-window video monitor. Audio output on 1-window video playback.9 VGA port VGA video output port. Output analog video signal. It can connectto the monitor to view analog video.10 RS232 port It is for general COM debugging to configure IP address andtransfer transparent COM data.11 GND.2.2.4 NVR4208-8P-IThe figure is for reference only. The actual product shall prevail.