If you are using the physical alarm inputs on the back of an L Series NVR (only supported by certain models) you will need to wire your alarm cables in to the Alarm1 or Alarm 2 and Ground (GND).
NVR alarm input connection
You set the normally open or normally closed state of the alarm from the alarm NVR's main menu under the 'Alarm' section by selecting the correct option from the 'Alarm Input Type' drop-down.
Alarm input 1 will trigger alarms on channel number 1 on the NVR, alarm input 2 will trigger channel number 2 on the NVR.
If you require more alarm inputs it is recommended to wire the required alarms in to the NO/NC connections on the camera’s connected to channels 3 to 16 (Please check that your cameras connected to these channels support DI/DO hard wired alarms). You then set the NVR ‘Alarm Input Type’ on channels 3 – 16 to ‘IP Camera’ and this will allow the NVR to receive a remote alarm from the relevant IP camera.