PICmicro微控制器的标准的模拟电话线连接

Thisapplicationnotedescribeshowtoconnecta

PICmicromicrocontrollerdevicetoastandardanalog

telephonelineinordertosendandreceivesingleand

multiplefrequencysignalsthroughmodulationand

demodulation(i.e.,MODEM).Althoughtherearemany

differentelementswithinamodemsystem,weareonly

concernedherewiththelineconnection.AN854ConnectingaPICmicroMicrocontrollertoaStandardAnalogTelephoneLineFigure1showshowtheringandtiplinesrunintotheAuthor:DavidHedleyprimaryofatransformer.ThehookswitchonthelineMicrochipTechnologyInc.sideofthetransformerisnotshownbutcanbeimple-mentedwithopto-couplers,relaysorswitches.Whena