【摘要】 针对老人单独在家出现意外情况后,通过无线紧急呼救系统呼叫自己的家属,实现一键自动呼叫所有设置的号码,直到接通,手持端可以直接与家属通话。控制系统以AT89C51单片机为工作核心,以MT8880实现对接收到的报警信号进行处理。该设计基于电话网络开发,紧急呼救的手持端通过MC13175/13176与RX3400芯片发射信号出去,接收端采用相同的芯片把DTMF信号发送至电话网,实现异频双式通信。更多还原

【Abstract】 For old people who is alone at home when they are emergency,through wireless SoS calling their relatives.Basing on the telephone net,the system refers to the AT89C51 single chip as core of control unit,and refers to MT 8870 chip as the main part of the receptions.It is based on the telephone system.The handset transmits the signals by MC13175/13176 and RX3400,while the reception transmits the DTMF signals in a similar way.Duplex frequency is finished.Transmitting the message of digital and voice through the telephone control system,the control part of the receiver transmits the signals of DTMF from the telephone net.更多还原