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1、输嘧馅秤谮圪筋嗓鬓枷疬桢酎Serialcommunicationinterface橛胁案煲镒衫隔钤巍耆淖巳度RS-232andRS-485isthenormallyusedinterfacesatanytime,itnotonlybuiltineveryPC-set,butalsobuiltinanytypesofcomputerswhicharefrommicrocontrollertohostcomputers,andequipmentconnectedwiththem.ThegeneralusageofRS-232istoconnectamodern,theot
2、herarrangementswithRS-232interfacesincludeprinter,datacollectionmodule,testingdeviceandcontrolloop.RS-232canbealsousedinthesimplelinkofanytypeofcomputer.But,RS-485canbelinkwithseveraldevicesbymeansofalonglead,ithavesamefunction.捱枫耙糌额诊夥始径嗤层珉脐RS-232isdesignedtodealwiththecommunicationbetw
3、eentwoarrangementswithdistancelimitationfrom50to100ft,whichdependonPotterrateandtypeofelectriccable.BecauseofwideapplicationofRS-232port,itsotherusageistolinkanothertypeofadapterconvertedformtheport.痿牛隗茵鳗偃痞叨丞蟪飧铉莴Forexample,asimpleloopchangesaRS-232intoaRS-485port.Theportcanbelinkwithsev
4、eraldevicesbymeansofalonglead.Non-equilibriumleadisusedtolinkedtoRS-232.Althoughnon-equilibriumshouldsomethingavoidable,itonlyreferstotheelectricpropertyofthesignalinlead.Inanon-equilibriumlead,signalvoltageisappliedtoanotherlead,allhasanothertechnicalterm“signalend”.朔照眺赈耗倡鲂涫魂哓呱薨虱Advant
5、agesinRS-232谴白塄盈篦图德琏柠潍祸鲸蝉RS-232isusedeverywhere.EveryPC-sethasoneormoreRS-232ports.TherenewedcomputerssustainotherserialinterfaceslikeUSB.ButRS-232candomanythingswhichUSBcan’tdo.堀崩铽塥鲆挖鹁畏拧厝怨涪见Inthemicro-controllerinterfacechipcanbeeasilyusedtochangeintoRS-232.蓁乾驷诃本蹀凤鬲颚鸬俺八椿Thejointingdist
6、ancecanreach50-100ft.Manyexternalinterfacesarenotusedfortoolongdistance.ThelongestdistancejointofUSBcanreach16ft.ThedistancebetweenparallelprinterinterfaceonthePC-setandthehostcomputercanreach10to15ft,or30ftbyusingTypeTEEE-1284Bdriver.ButRS-232canusethelongerelectriccable.目钮仄剂瑰谛袖浙捏计黛锅餮I
7、feveryRS-232portislinkedwithamodern,Telephonenetworkcanusedtosenddataintherageoftheworld.疱媳愎拈刮街衬灬按蟆讳畲蚴Foradoublelink,3leadsareneeded.Aparallelcircuitgenerallyneeds8datalines,twoormorecontrolsignallinesandgroundwires。Itismoreexpensiveifmoreleadsandbiggerconnectorsareused.宸陀慝崔睁舷皆
