Luxul AMS-1208P, Быстрая настройка

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UNDERSTANDING POE
Power„over„Ethernet„(or„PoE)„is„a„system„which„passes„electrical„power„along„with„data„over„Ethernet„cabling.„This„
allows„a„single„cable„to„provide„both„data„connection„and„electrical„power„to„devices„such„as„wireless„access„points„or„
IP„cameras.„This„feature„can„simplify„network„installation„and„maintenance„by„using„the„switch„as„a„central„power„source„
for„other„network„devices.
There„are„several„common„techniques„for„transmitting„power„over„Ethernet„cabling,„and„two„have„been„standardized„by„
IEEE„802.3.„Power„may„be„transmitted„on„the„unused„conductors„of„an„Ethernet„cable,„or„by„applying„a„common-mode„
voltage„to„each„pair.„The„latter„is„similar„to„phantom„power„commonly„used„for„powering„balanced„microphones.
In„addition„to„standardizing„existing„practice„for„spare-pair„and„common-mode„data„pair„power„transmission,„the„IEEE„
PoE„standards„provide„for„signalling„between„the„power„source„equipment„(PSE)„and„powered„device„(PD).„This„signaling„
allows„the„power„source„to„sense„and„negotiate„the„amount„of„power„required„for„a„connected„device.
Power Budget
One„challenge„during„system„design„and„installation„is„to„consider„and„calculate„the„total„device„power„consumption„to„
ensure„it„is„less„than„the„total„power„budget„of„the„switch.„The„power„supply„in„the„switch„-„not„the„number„of„ports„-„
determines„your„total„power„budget.
For„instance,„the„AMS-1208P„AV„Series„Gigabit„Managed„Switch„features„a„total„PoE„power„budget„of„130„Watts.„If„you„
were„planning„an„8-camera„serveillance„system,„and„each„camera„consumed„10W,„your„total„power„consumption„would„
be„80W,„which„is„well„under„the„130W„total„power„budget.„However,„if„each„camera„consumed„20W,„total„consumption„
would„exceed„the„130W„total„power„budget.
Depending„on„the„devices„you„intend„to„connect,„you„may„need„a„larger„switch,„not„because„of„the„number„of„ports,„
but„because„of„the„total„power„budget.
Cable Length
Power„over„ethernet„(POE)„will„only„power„a„connected„device„if„there„is„enough„voltage„after„the„cable„run.„The„maxi-
mum„cable„run„for„PoE„devices„is„approximately„300ft„(100m).„Beyond„this„point,„voltage„will„drop„and„become„unstable.„
If„you„need„to„connect„PoE„devices„more„than„300ft„from„a„switch,„PoE„extenders„are„available„for„that„application.