... protection functionDesktop or wall mountingMonitoring, warning, remote door releasingNight visioncall/volume/contrast adjustableSupport software update.Supports ... 4-channel CCTV video inputs, 2-channel video door phone inputs)4 channel monitor or single on ... are optional AccessoriesMonitor,Desktop Bracket,Wall-mounted bracket,AC power adaptor,Remote controller,Outdoor Station,Angle Bracket, ...