Power over ethernet?

[Shinigami-Sama]

hey all, I"m doing a school project and I'm wondering if anyone has any links and such for information about power over ethernet, I've been searching around for a lil bit and I"m getting mostly distributors with little objective information.

thanks for the help all

[Sirber]

http://www.nycwireless.net/poe/

[Doom9]

how about searching the ieee site? 802.3af is the standard iirc. I have a couple of switches and phones at work that make use of it at work.. pretty darned useful.

[Qjimbo]

Thats really cool, hmm computers run on 12V, I wonder if you could power a MiniITX box over ethernet O_o that'd be sweet ^^;

[Shinigami-Sama]

how about searching the ieee site? 802.3af is the standard iirc. I have a couple of switches and phones at work that make use of it at work.. pretty darned useful.
I was looking there, but I got lost in it, and yes it is 802.3af, theres a new one being developed too

also weather its usefull o not depends on your point of veiw, running 48V D/AC(conflicting information on weather ac or dc, probly due to the differt verstions of the standard and propritory apps) across your cat5e cable seems a bit dangerous, and the new standard will be up to 45W across it, appearntly, seeing as how the current is min13W, max 12.9W, and full 15.4W, see my problem?
to much conflict, but now that I'm not quite as stressed over it I'll see if I can actauly find any usefull information on the IEEE site, its fairly difficult to find information on that site I"ve noticed, and a standards book well out of a normal person's price range, especialy a student this is proving difficult, but thanks for the help

edit~

also this having to be up to Gbit-cat6 standards makes this even more difficult

[arch_angel16]

What's there to tell? Some vendors use the spec 48 DCV and some don't. Power over ethernet is mostly used to power enterprise-level wireless access points. The question of "why" comes up here. These access points are usually mounted in a plenum-rated ceiling (look that word up, it basically means fire-retardant) and since plenum ceilings are 1 - frikkin expensive and 2 - annoying to spec and install and certify, the less wires - the better.

All POE does is inject a 48V DC offset into the ethernet transmission, which is removed at the endpoint.

[Doom9]

As a student you can normally ask faculty... depends on what kind of student you are of course.. I was at an engineering college so I was able to get access to all IEEE and ACM publications. Some IEEE standards are also freely available though, for instance the 802.11 ones (that's WLAN for you). I wouldn't bother with pre-standards much.. the IEEE ratification process is slow and messy and you never really know what the end result will be. My master's thesis touched WLAN and when I started, the 802.11e ratification (QoS) was supposed to happen while I was still working on my thesis, now it's almost three years later and it still has not been ratified.. so whatever I might have written about the e standard at that time, might not apply today anymore. Still, if you want the tech scoop, there's no way around the IEEE specs.. they sure are a hard read (just as are most specs document), but if you understand those, you'll know the standard for sure.

[Shinigami-Sama]

well I know that much so far, but I need objective information for part of the report, but even the IEEE standards document is convoluted, I saw 2 conflicting power outputs, so theres some more to re-read and and such