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Power-over-Ethernet: IEEE 802.3af Draft
SkewlD00d writes "Want power (~10W) and your fat 10/100Mbps pipe (1Gbps maybe) on the SAME jack. Surf the web and recharge your handheld w/o finding its clunky base/transformer, home automation, and control systems are just some of the possibilities. Using suitable hubs/switches or dongle, power can be provided over unused pairs, or possibly raise the signal offset above DC, X10-style (no link, u know why). See IEEE 802.3af DTE Power via MDI Task Force. Maxim (not that one :o) already has some goodies. They have schematics for 8.25W/12.5W single-output and 14.2W triple-output 802.3af PSU. Try FindChips if you're looking for them; they're in production and are NOT vapor-ware!"
Not sure how standard it is, but many Cisco switches support Inline Power, which is used by their Voice-Over-IP Phones. We deal with this constantly where I work.
It can be annoying because if you want to run several phones on one drop, they need power supplies if you don't want to use an expensive inline power capable switch.
from here
Ethenet-over-power, short range for home and long range for ISPs, currently being deployed in the U.S. Check it out.
Here's a useful how-to on powering wireless base stations using Power-Over-Ethernet (POE). Several wireless vendors already sell POE kits for wireless APs. Here's a POE kit for the AirPort.
Power+Ethernet over one wire is a great combination for settting up APs, because many of the interesting places to put a wireless access point (e.g., in the attic, by the pool, in the middle of the ceiling) may not have a power outlet nearby, or you may simply not want to run two sets of wires (AC power + ethernet) to the location.
-Mark
I can smell burning...
Jon
Number one cause of device failure for SCSI devices: power shorts on SCSI chain.
Number one cause of device and motherboard failure for Firewire devices: power shorts on Firewire chain.
Notice a pattern?
There's good reason to have two cables running to each device: when a cable inevitably goes bad or the user mis-mates a hot connection, the chance for device damage is minimal.
"You have liberated me from thought."
From the post, they are talking about around 10 Watts, Assuming that they are pushing that at 12V (Sorry, not read the spec - it's not worth the $80-odd the IEEE wants for it!!), that comes out at a little over 830mA.
I can't remember the Power / Voltage / Current ratings of 10/100/1000 Ethernet off the top of my head, but I'd say that a short accross Power to one of the Ethernet conductors should just cause data to 'stop' in the direction of the short (Rx / Tx).
I say this because I have frequently (accidentally) connected Ethernet cards to the POTS/PSTN Switch over the sturctured cabling at work, whilst the port I am connecting to is Ringing - which is usually pushing more power than is being talked about here - and the Ethernet cards still live on...
On the flip side, a Short between +Ve and 0V on the power could generate quite a bit of heat in the cable, until a breaker / fuse was tripped, which could be a fire hazard, but as long as the power 'output' device has a 1A 'fast-blow' type fuse in place, the cable will certainly live without causing major damage - the fuse would blow before the cable even started to get warm!
There is the potential for damage yes, but at the power levels being discussed, it's a very small potential...
Disclaimer: I meant what I thought, not what I wrote! What? You can't read my Mind? Oh dear!
I already have tethered power. But riddle me this, batman: when am I gonna get power over WIRELESS ethernet?
I'm willing accept a little sparking.
Hey freaks: now you're ju
This spec has been out a while now... 2 years ago PowerDsine made a prototype ethernet-powered razor - here's coverage from more traditional network press
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