PLANET NVR-1620 - Manual (Page 82)

Network Video Recorder with HDMI
NVR‐820 / NVR‐1620
82
Define which system events should trigger the recorder to send out
notifications.
Define how the notifications will be sent and where they will be sent.
Event trigger may not work for cameras that are placed outside of
your local network or on the Internet until the “UPnP Port
Forwarding” is enabled in both the NVR and the router.