Use the high-definition of 3.5 "digital display screen; The level angle of camera is 90 degrees,so that it is more convenient for people to know who is coming. Both of Launch, receive depending on digital encryption and frequency technic, , strong anti-interference and high degree of confidentiality; Use full-duplex mode intercom calls, voice clarity Hands-free calling function; Use the built-in rechargeable lithiumion battery-powered, with automatic recharging function. And Calendar, time in a separate power supply; indoor unit can Wall-mounted or Desktop, and can be moved at any time, so you can know or see your guests at any time and location. Instruction function of charge, standby function Instructions It with menu features. indoor and outdoor voice, intercom size, brightness, contrast, regulation of calendar time are adjustable, the number of the out door units and the number of the indoor units can be controled by yourself throught the function of process set-up. The system with visitors picture storage function, when a visitor came in The picture of memory can be stored in Wireless control and electronic control Hyun ringtones and indoor units options Transmission distance in open terrain c Use 2.4G frequency transmission