... 3.network function IP video door phone, DVR video door phone,Video door phone, 4CH video door phone. 2-way audio communication ... *Password protection function*Desktop or wall mounting*Monitoring, warning, remote door releasing*Night vision*8call/volume/contrast adjustable*Support software ... input(4-channel CCTV video inputs, 2-channel video door phone inputs)*4 channel monitor or single on screen ...