Ib lub modem hloov cov ntaub ntawv mus rau lub teeb liab kom nws tuaj yeem xa tau yooj yim thiab tau txais hauv xov tooj, cable, lossis satellite txuas. Rau kev sib kis ntawm kab xov tooj analog-uas yog ib qho kev nyiam tshaj plaws rau kev nkag mus rau hauv internet-lub modem hloov cov ntaub ntawv ntawm analog thiab digital hom hauv lub sijhawm tiag tiag rau kev sib txuas lus hauv ob txoj hauv kev. Nyob rau hauv cov ntaub ntawv ntawm high-speed digital modems nrov niaj hnub no, lub teeb liab yog ntau yooj yim thiab tsis xav tau cov analog-rau-digital conversion.
Dab tsi yog Modem hauv Computer Networking?
History of Modems
Cov khoom siv thawj zaug hu ua modems hloov cov ntaub ntawv digital rau kev sib kis ntawm cov xov tooj analog. Qhov ceev ntawm cov qauv no tau ntsuas hauv baud (ib chav ntsuas lub npe tom qab Emile Baudot), txawm hais tias raws li kev siv tshuab computer tsim, cov kev ntsuas no tau hloov mus rau hauv cov khoom ib ob. Thawj cov qauv kev lag luam tau txhawb nqa qhov nrawm ntawm 110 bps thiab tau siv los ntawm US Department of Defense, cov kev pabcuam xov xwm, thiab qee qhov kev lag luam loj.
Modem maj mam paub rau cov neeg siv khoom thaum xyoo 1970s txog rau xyoo 1980s raws li cov ntawv xov xwm pej xeem thiab cov kev pabcuam xov xwm zoo li CompuServe tau tsim los ntawm kev siv internet thaum ntxov. Tom qab ntawd, nrog kev tawg ntawm Ntiaj Teb Wide Web nyob rau nruab nrab thiab lig xyoo 1990, dial-up modems tau tshwm sim los ua thawj hom kev siv internet hauv ntau tsev neeg thoob ntiaj teb.
Dial-Up Modems
Modem siv rau hauv kev sib txuas hauv xov tooj hloov cov ntaub ntawv ntawm daim ntawv analog siv ntawm cov xov tooj thiab daim ntawv digital siv hauv computers. Ib qho xov tooj sab nraud modem ntsaws rau hauv lub computer ntawm ib qho kawg thiab ib lub xov tooj ntawm qhov kawg. Yav dhau los, qee cov neeg tsim khoom siv computer tau koom ua ke nrog kev hu xov tooj rau hauv lub computer.
Niaj hnub nimno dial-up network modems xa cov ntaub ntawv ntawm qhov siab tshaj plaws ntawm 56,000 khoom ib ob. Txawm li cas los xij, qhov kev txwv tsis pub muaj ntawm cov xov tooj pej xeem feem ntau txwv cov ntaub ntawv modem rau 33.6 Kbps lossis qis dua.
Thaum koj txuas mus rau ib lub network los ntawm dial-up modem, modem relays los ntawm tus neeg hais lus lub suab sib txawv ntawm koj lub cuab yeej thiab cov chaw taws teeb modem. Vim tias cov txheej txheem kev sib txuas thiab cov qauv ntaub ntawv zoo sib xws txhua zaus, hnov lub suab qauv pab koj xyuas seb cov txheej txheem txuas puas ua haujlwm.
Broadband Modems
A broadband modem zoo li cov siv rau DSL lossis cable internet nkag tau siv cov txheej txheem tshaj tawm cov txheej txheem kom ua tiav cov network nrawm dua li cov qauv hu ua ntej. Broadband modems feem ntau hu ua high-speed modems. Cellular modems yog hom digital modem uas tsim kev sib txuas hauv internet ntawm lub xov tooj ntawm tes thiab lub xov tooj ntawm tes.
Lo lus modem yog mashup ntawm lub sij hawm modulation / demodulation, uas yog lub ntsiab lus rau kev hloov dua siab tshiab ntawm digital thiab analog signals.
Sab nraud broadband modems ntsaws rau hauv lub tsev broadband router lossis lwm yam khoom siv hauv tsev ntawm ib kawg thiab sab nraud internet interface xws li cable kab ntawm lwm qhov. Lub router lossis lub rooj vag qhia cov teeb liab rau txhua yam khoom siv hauv kev lag luam lossis hauv tsev raws li xav tau. Qee qhov broadband routers suav nrog kev sib xyaw modem ua ib chav kho vajtse.
Ntau tus neeg muab kev pabcuam hauv internet broadband muab cov khoom siv kho mob tsim nyog rau lawv cov neeg siv khoom yam tsis tau them nqi lossis them tus nqi txhua hli.
FAQ
Wi-Fi modem yog dab tsi?
A Wi-Fi modem muaj peev xwm tshaj tawm cov teeb liab wireless (tseem hu ua Wi-Fi network) thiab kev sib txuas ib txwm muaj. Niaj hnub no, feem ntau modems tuaj nrog kev txhawb nqa hauv Wi-Fi.
Qhov txawv ntawm lub router thiab modem yog dab tsi?
Hnub no, tsis ntau. Feem ntau niaj hnub modems thiab routers sib koom ua haujlwm zoo ib yam. Txawm li cas los xij, kev lig kev cai, modem tswj koj qhov kev sib txuas rau hauv internet. Lub router yog lub luag haujlwm rau kev tso cai rau ntau lub cuab yeej txuas rau hauv internet ib txhij-thiab nws ua rau cov khoom siv sib txuas lus yam tsis tau nkag mus rau hauv internet.
