InputOutputdevices输入输出设备

《InputOutputdevices输入输出设备》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、devices...InputsandOutputKeyboardThecommonestwaytoenterdataintoacomputer.Eachkeyissimplyaswitch,whichwhenpressed,resultsinadigitalcodebeingsenttothecomputer.MouseThemovementofthemouseoveraflatsurfaceismirroredbyapointeronthemonitorscreen.Underthemousei

2、saballwhichrollsandturnstwoshafts,oneforeachdirection-left/right&up/down.Buttonsonthemouseenableselectionstobemadefrommenus,movementofobjectsaroundthescreen,andpaintingordrawing.TouchsensitivescreenThisdeviceactslikeamousethattheusercanmovebytouchingth

3、escreen.Itisusedbypeoplewhofindusingamousedifficult,tootimeconsumingorifitmightgetstolen/damaged.BarcodereaderThebarcodeditemisswipedoveralaserscannerisswipedoverthebarcodetoreadinthedata.Itisthesameasascannerbutduetothesimplenatureofthebarcodethescann

4、ingisveryrapid.ScannerLikeaphotocopieritscansafullpagewithlaserlightbutinsteadofprintingcopies,ittransmitstheimagetothecomputerasdigitalcode,whichcanbesavedasafile.Ineffect,itperformstheexactoppositefunctiontoaprinterbyconvertingaprintedpageintoacomput

5、erfile.SpeechsynthesiserOutputdeviceusedtohelppeoplewhocan’tseevisualoutputsfromthecomputer.Itproducesahuman-likevoice.DigitalcameraLightreceivedthroughthelensisconvertedtodigitalsignalsbysensors,ratherthanstoredbychemicalchangeonafilmasinanormalcamera

6、.Theresulting"photograph"canthenbestoredonacomputerandusedjustlikeanyclipartfiles.OtherdevicesMagneticstripreader-usedoncreditcardtypedevices.Theinformationisstoredonthetapeonthebackofacard.Themachinecanreadandwritetoit.Opticalmarkreader-similartoabarc

7、odereaderbutusesinfra-redlighttoscanpencilmarksonpreparedformssuchasmultiple-choiceexaminationanswersheetsorlotterytickets.Opticalcharacterreader-usesanordinaryscannertotakeaphotographicimageofprintedorevenhand-writtentext.Specialsoftwarethenlooksatthe

8、image,recogniseseachcharacterandconvertsitintoatextfileOtherdevicesMagneticinkcharacterrecognition-usesinkcontainingmagneticparticles.Thismethodisusedbybankstoprintonachequetheamountthatitismadeoutfor,thenitisscannedintoacomputer.Printe