多带滤波器功能的双音频（dtmf）接收器，可工作在下电模式和抑制模式，并可用数字化计算方法来识别，以
duo dai lv bo qi gong neng de shuang yin pin dtmf jie shou qi ke gong zuo zai xia dian mo shi he yi zhi mo shi bing ke yong shu zi hua ji suan fang fa lai shi bie yi
话线路的接通。最终使整个电路完成自动模拟摘机过程。3dtmf接收电路ht9270是综合了数字解码器和
hua xian lu de jie tong zui zhong shi zheng ge dian lu wan cheng zi dong mo ni zhai ji guo cheng 3dtmf jie shou dian lu ht9270 shi zong he le shu zi jie ma qi he
电器jl，因此线路会处于导通状态。控制电路可向交换机发出模拟摘机信号，交换机响应摘机信号后便可完成电
dian qi jl yin ci xian lu hui chu yu dao tong zhuang tai kong zhi dian lu ke xiang jiao huan ji fa chu mo ni zhai ji xin hao jiao huan ji xiang ying zhai ji xin hao hou bian ke wan cheng dian
挂机指令由单片机判断i／o口是否为高电平来实现。由于振铃检测后，系统会给另一个i／o高电平从而开启继
gua ji zhi ling you dan pian ji pan duan i o kou shi fou wei gao dian ping lai shi xian you yu zhen ling jian ce hou xi tong hui gei ling yi ge i o gao dian ping cong er kai qi ji
示。该模拟摘挂机电路主要由二个三极管开关电路控制继电器开关。继电器则控制接入电话线两端的信号接入。摘
shi gai mo ni zhai gua ji dian lu zhu yao you er ge san ji guan kai guan dian lu kong zhi ji dian qi kai guan ji dian qi ze kong zhi jie ru dian hua xian liang duan de xin hao jie ru zhai
便停止铃流发送，并将线路电压变为十几伏的直流以完成接续。根据有关技术指标，模拟摘挂机电路设计如图3所
bian ting zhi ling liu fa song bing jiang xian lu dian ya bian wei shi ji fu de zhi liu yi wan cheng jie xu gen ju you guan ji shu zhi biao mo ni zhai gua ji dian lu she ji ru tu 3 suo
话机将通过叉簧接上约300的ω的负载，从而使整个电话线回路流过约30ma的电流。交换机检测到该电流后
hua ji jiang tong guo cha huang jie shang yue 300 de de fu zai cong er shi zheng ge dian hua xian hui lu liu guo yue 30ma de dian liu jiao huan ji jian ce dao gai dian liu hou
"r"键藏熬的电子电话机的摘机状态直流电阻应小于350ω。挂机状态下的漏电流小于5μa。当用户摘机时，电
"r" jian cang ao de dian zi dian hua ji de zhai ji zhuang tai zhi liu dian zu ying xiao yu 350 gua ji zhuang tai xia de lou dian liu xiao yu 5 a dang yong hu zhai ji shi dian
图2所示。2模拟摘挂机电路根据国家有关标准规定：不论任何电话机，摘机状态的直流电阻应小于300ω，有
tu 2 suo shi 2 mo ni zhai gua ji dian lu gen ju guo jia you guan biao zhun gui ding bu lun ren he dian hua ji zhai ji zhuang tai de zhi liu dian zu ying xiao yu 300 you
中断采用定时查询方式。响铃四次后，单片机将控制继电器模拟摘机，以完成振铃音藏熬的检测。振铃检测电路设计如
zhong duan cai yong ding shi cha xun fang shi xiang ling si ci hou dan pian ji jiang kong zhi ji dian qi mo ni zhai ji yi wan cheng zhen ling yin cang ao de jian ce zhen ling jian ce dian lu she ji ru
合器和电位器共同组成振铃信号变换电路。它们使输入电压和电流输出到单片机at89c52的i／o口。系统
he qi he dian wei qi gong tong zu cheng zhen ling xin hao bian huan dian lu ta men shi shu ru dian ya he dian liu shu chu dao dan pian ji at89c52 de i o kou xi tong
摘机，便由单片机控制自动模拟摘机。电话振铃信号通过电容隔直、电阻限流、整流桥的整流、电阻分压、光电耦
zhai ji bian you dan pian ji kong zhi zi dong mo ni zhai ji dian hua zhen ling xin hao tong guo dian rong ge zhi dian zu xian liu zheng liu qiao de zheng liu dian zu fen ya guang dian ou
能。其系统框图如图1所示。藏熬1振铃检测电路当振铃电路检测到铃流信号时．以响铃四次为准，即响铃四次后无人
neng qi xi tong kuang tu ru tu 1 suo shi cang ao 1 zhen ling jian ce dian lu dang zhen ling dian lu jian ce dao ling liu xin hao shi yi xiang ling si ci wei zhun ji xiang ling si ci hou wu ren
、烟雾传感器)检测到异常信号时，也会产生报警信号，信号通过接口电路和电话网传输到用户以实现自动报警功
yan wu chuan gan qi ) jian ce dao yi chang xin hao shi ye hui chan sheng bao jing xin hao xin hao tong guo jie kou dian lu he dian hua wang chuan shu dao yong hu yi shi xian zi dong bao jing gong
89c52藏熬接收到信息后，便可对家庭安装的各种电器进行开机、关机作，同时当本装置中的传感器(红外热释电
89c52 cang ao jie shou dao xin xi hou bian ke dui jia ting an zhuang de ge zhong dian qi jin hang kai ji guan ji zuo tong shi dang ben zhuang zhi zhong de chuan gan qi ( hong wai re shi dian
测、双音频dtmf识别等。用户利用任意一部具有双音多频电话或手机均可通过电话网传输dtmf信号。at
ce shuang yin pin dtmf shi bie deng yong hu li yong ren yi yi bu ju you shuang yin duo pin dian hua huo shou ji jun ke tong guo dian hua wang chuan shu dtmf xin hao at
提供单片机与电话外藏熬线的接口及传感器的信号输入接口。其中电话网接口电路包括铃流检测、摘挂机控制、忙音检
ti gong dan pian ji yu dian hua wai cang ao xian de jie kou ji chuan gan qi de xin hao shu ru jie kou qi zhong dian hua wang jie kou dian lu bao kuo ling liu jian ce zhai gua ji kong zhi mang yin jian
形成各种控制信号，最终完成各种信息(振铃信号、dtmf信号、语音信号、报警信号)的记录；接口电路用于
xing cheng ge zhong kong zhi xin hao zui zhong wan cheng ge zhong xin xi ( zhen ling xin hao dtmf xin hao yu yin xin hao bao jing xin hao ) de ji lu jie kou dian lu yong yu
自动报警系统。本系统由单片机．at89c52构成主控部分．以进行主要藏熬的信息处理。从而接收外部作指令以
zi dong bao jing xi tong ben xi tong you dan pian ji at89c52 gou cheng zhu kong bu fen yi jin hang zhu yao cang ao de xin xi chu li cong er jie shou wai bu zuo zhi ling yi
标签：at89c52 引言本系统是以at89c52单片机作为控制核心的一种新型家用智能电话控制电器和
biao qian at89c52 yin yan ben xi tong shi yi at89c52 dan pian ji zuo wei kong zhi he xin de yi zhong xin xing jia yong zhi neng dian hua kong zhi dian qi he