Lub hwj chim dhau Ethernet (PoE) yog lub tshuab xa hluav taws xob thiab cov ntaub ntawv los ntawm cov kab hluav taws xob network (twisted khub cables). Nws tso cai rau cov ntaub ntawv teeb liab xws li video thiab suab xa mus ib txhij ntawm tib lub network cable, thiab muab DC fais fab mov (feem ntau 48V) rau cov khoom siv. PoE thev naus laus zis feem ntau yog siv hauv IP davhlau ya nyob twg xws li IP xov tooj, wireless access point (APs), network koob yees duab, thiab daim npav nyeem ntawv, kom cov cuab yeej no tuaj yeem tau txais lub zog xav tau thaum nkag mus rau hauv lub network, tsis tas yuav xav txog qhov teeb meem ntawm kev siv hluav taws xob. cais.
Qhov zoo ntawm PoE thev naus laus zis yog tias nws yooj yim rau kev xaim ntawm cov khoom siv hauv lub network, txo tus nqi ntawm kev tsim lub network, thiab txhim kho kev ntseeg tau thiab yooj yim ntawm cov khoom siv. Los ntawm PoE, cov tuam txhab tuaj yeem txuag cov nuj nqis loj ntawm kev yuav khoom thiab txhim kho ntau lub qhov hluav taws xob, thaum paub txog kev tswj cov chaw taws teeb ntawm lub hwj chim rau thiab tawm haujlwm.
Txhawm rau kom tus qauv tsim thiab txhawb kev txhim kho ntawm PoE fais fab mov thev naus laus zis, IEEE Standards Committee tau tshaj tawm ntau tus qauv PoE, suav nrog IEEE 802.3af, IEEE 802.3at, thiab IEEE 802.3bt. Cov qauv no muaj cov ncauj lus kom ntxaws txog cov khoom siv hluav taws xob, kev xa hluav taws xob, kev txais tos, kev faib cov khoom siv, thiab kev sib tham txog kev sib tham ntawm cov khoom siv hluav taws xob PoE.
Hauv PoE system, cov cuab yeej siv hluav taws xob (PSE) thiab cov cuab yeej siv hluav taws xob (PD) xa hluav taws xob los ntawm ib qho hluav taws xob tshwj xeeb khub. Raws li IEEE tus qauv, cov hlua fais fab tuaj yeem muab faib ua ob hom kev siv hluav taws xob: Hloov A (1/2 thiab 3/6 khub) thiab Hloov B (4/5 thiab 7/8 khub). Txawm li cas los xij, IEEE tus qauv tsis tso cai rau kev thov ib txhij ntawm ob hom kev siv hluav taws xob saum toj no. Cov cuab yeej siv hluav taws xob tsuas tuaj yeem muab ib qho kev siv xwb, tab sis cov cuab yeej siv hluav taws xob yuav tsum tuaj yeem hloov kho rau ob qho xwm txheej tib lub sijhawm.
Cov txheej txheem kev sib tham ntawm PoE fais fab mov suav nrog cov kauj ruam ntawm kev kuaj xyuas cov cuab yeej siv hluav taws xob, sib tham txog lub peev xwm muab hluav taws xob, pib lub zog hluav taws xob, ib txwm siv hluav taws xob thiab hluav taws xob tawm. Thaum lub sij hawm muab hluav taws xob cov txheej txheem, PSE yuav saib xyuas kev siv hluav taws xob ntawm PD hauv lub sijhawm tiag tiag thiab ua kom muaj kev tswj xyuas hluav taws xob tsim nyog. Thaum lub hwj chim noj ntawm PD tsis nyob rau hauv theem ntau, PSE yuav txiav txim siab tias PD nyob rau hauv ib qho kev txawv txav thiab disconnect lub fais fab mov kom rov pib dua qhov kev tshawb nrhiav tom ntej.
Feem ntau, PoE thev naus laus zis tau siv dav thiab txhawb nqa hauv kev lag luam thiab kev sib txuas hauv tsev nrog nws qhov tshwj xeeb zoo. Nrog rau kev txhim kho txuas ntxiv thiab txhim kho thev naus laus zis, PoE thev naus laus zis yuav tsum tau ua lub luag haujlwm ntau dua hauv ntau thaj chaw.
