Wide Compatibility Compatible with NVR supporting Protocol On Vif, and also work with Hiseeu PoE NVR like YNVR-P-8 or Hiseeu PoE Camera System ASIN:B07HRKDD6B,B088YP8LPY, B09DV1CBXR,B0B4SCDZM7,B08XXGZVT2,B09DTZ559W, etc. Real Time 2-Way AudioWe can talk directly on phone app for asking courier to put package to a certain place you point, and hear sound from app or TV monitor connected to NVR