Currently this is still the best preventative option for protecting a perimeter fence or boundaries of any premises.
The camera picks up an intrusion near the fence either via the built-in thermal camera, or Acusense AI deep-learning Line Crossing triggers on the latest model CCTV D/N cameras.
A built-in audio warning message is played via the built-in speaker (10m) or via the added horn speakers (60m+).
Reaction to the trigger can also include: video monitoring company responding with live audio to address the intruder OR a Notification on your App OR a pop-up image on the screen of the DVR/NVR in a guardhouse, home, etc.
2-Way communication is available to address any person in sight of the camera.