/DO signals to trigger devices such as alarms or lights- View cameras from multiple servers- Support one way audio (1ch and Main stream only)Supported Mobile Devices: Supported OS: - Android v2.3 - Android v4.0 - Android v4.1- Android v4.2- Android v4.3- Android v4.4 Supported Video codec:- MJPEG, MPEG4, H.264 (Mainstream) Supported products:- D-ViewCam DCS-210 v1.1 and above- D-ViewCam DCS-220 v1