6、sicsandTelecommunicationEngineeringofShaanxiUniversityofTechnology,Hanzhong,Shaanxi)Tutor:Abstract:In this paper discrible a new design mobile alarming unit system based on GSM is introduced. The new alarming system uses STC89C51 series chips which provide high cost - performance , and SIM900A c
7、ommunication unit which supports GSM. It possesses the properties such as long distance available ,no noise pollution ,and bilateral controlling ,avoiding the disadvantages such as short distance ,pollution ,noise of the com