[PLUG] What is POE?

[Fred James]

Russell Senior wrote:
>>>>>> "Joe" == Joe Pruett <joey at clean.q7.com> writes:
>>>>>>             
>>> Power over Ethernet and how is it implemented?  I'm tempted to grab
>>> 2 Invictus wireless outdoor WAPS, but I'm concerned about what POE
>>> is since they use it.
>>>
>>> http://www.invictuswireless.com/ProductDetails.asp?ProductCode=NS2
>>>       
>
> Joe> poe is quite nice.  it lets you use the standard ethernet twisted
> Joe> pair connection to deliver power to small bits of hardware (voip
> Joe> phones, waps, etc).  you can get a poe switch to provide power,
> Joe> or poe injectors to add poe to a single run.
>
> Just beware that not all PoE powered devices are IEEE Standard 802.3af
> PoE.  Lots of devices I deal with are something called "passive" poe
> where there is no handshaking protocols, and the end devices are
> typically expecting less than the "standard" 48V.  For example,
> virtually all of the Ubiquiti gear uses "passive" PoE in the range
> from about 10-24 Volts or something (from memory, please check).  The
> Nanostation comes with a little injector that just puts a nominally
> 12V DC power supply on the ethernet cable (two wires +12V, two wires
> ground).  There is some resistive voltage loss in long runs of
> cabling.  It is not uncommon for people to use 15V or 18V in
> situations like that.  In anything under about 100 feet, the supplied
> 12V adapter is going to be just fine.
>   
Any disadvantage/corruption from running power over the Ethernet cable?
Regards
Fred James