... 3.network function IP video door phone, DVR video door phone,Video door phone, 4CH video door phone. 2-way audio ... *Desktop or wall mounting*Monitoring, warning, remote door releasing*Night vision*8call/volume/contrast adjustable*Support ... 4-channel CCTV video inputs, 2-channel video door phone inputs)*4 channel monitor or single on ... 100,000sec; 1/50-1/100,000sec Operation Temperature: -10°C ~ 45 °C