Ua ntej, cia peb nkag siab cov yam ntxwv tseem ceeb ntawm RS232 thiab USB. RS232 yog tus qauv kev sib txuas lus ib txwm muaj uas tau muaj nyob rau ntau xyoo lawm. Nws feem ntau yog siv los txuas cov khoos phis tawj thiab cov khoom siv sab nraud, xws li modems, tshuab luam ntawv, thiab cov nas serial. RS232 siv cov ntaub ntawv sib kis, uas txhais tau hais tias xa cov ntaub ntawv me ntsis los ntawm me ntsis. Ntawm qhov tod tes, USB (Universal Serial Bus) yog tus qauv kev sib txuas lus niaj hnub no txhawm rau muab kev nrawm dua thiab dav dua cov cuab yeej siv tau. USB txhawb kev sib kis ntawm ntau cov ntaub ntawv me me, yog li ntau bytes ntawm cov ntaub ntawv tuaj yeem xa mus rau hauv ib qho kev sib kis.
Hais txog kev ceev, USB feem ntau yog nrawm dua RS232. USB muaj ntau yam versions, txhua tus muab qhov sib txawv siab tshaj plaws hloov ceev. USB 2. Hauv qhov sib piv, qhov sib kis ceev ntawm RS232 feem ntau qis dua, feem ntau nyob ib ncig ntawm 115.2 Kbps. Yog li ntawd, nyob rau hauv cov nqe lus ntawm ntshiab kis ceev, USB yog feem ntau sai.
Txawm li cas los xij, txhawm rau ntsuas lawv qhov kev ua tau zoo, lwm yam yuav tsum tau xav txog. Ua ntej, RS232 feem ntau haum rau kev sib txuas lus ntev, thaum USB muaj qhov sib kis luv luv. Qhov no ua rau RS232 siv tau ntau dua hauv qee qhov xwm txheej tshwj xeeb, xws li cov xwm txheej uas yuav tsum muaj kev sib txuas lus ntev ntawm cov khoom siv.
Qhov thib ob, RS232 yog ib qho kev sib txuas lus asynchronous, thaum USB tuaj yeem txhawb nqa ob qho tib si synchronous thiab asynchronous kev sib txuas lus. Kev sib txuas lus Asynchronous txhais tau hais tias cov ntaub ntawv raug xa tawm ntawm qhov tsis sib xws, thaum synchronous kev sib txuas lus synchronously xa cov ntaub ntawv raws li lub moos teeb liab. Hauv qee cov ntawv thov tshwj xeeb, kev sib txuas lus asynchronous yuav tsim nyog dua, thiab RS232 muaj qhov zoo ntawm qhov no.
Tsis tas li ntawd, USB feem ntau yooj yim siv thiab teeb tsa. Thaum ntsaws thiab tshem tawm cov khoom siv, USB cov cuab yeej raug kuaj pom thiab teeb tsa los ntawm lub kaw lus, thaum RS232 feem ntau xav tau phau ntawv teeb tsa. Qhov no ua rau USB ntau tus neeg siv-phooj ywg thiab ntsaws thiab ua si zoo.
