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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.
You just need one of these. http://home.t-online.de/home/w.robel/m_mcbike/humo r_2/ethernetkiller.jpg
Life is not for the lazy.
Telephone voltage use to charge PDA!
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 just see it -- I fry myself inserting the Ethernet cable in the card. Instructions read: before inserting, go to your power panel, can shut off the circuit breaker for your computer and then...
SPAM solution made easy: 1 spammer, 5 cords of rope, 5 hourses, and fireworks. Be creative.
>X10-style (no link, u know why)
:-/
No I don't!
Why??
Maxim(-ic.com) (not that one :o)
Yeah, I know *everyone* here was thinking of Maxim.com...hehe
Sleesebags =P
Moderation: +4. Modded 70% Funny and 30% Overrated. 100% Saturated.
The latest firewire standard can do 800Mb and provide up to 45W of power
I use this extensively with my Lucent/Orinoco wireless APs. Been doing it for about 2 years now. It's also part of 3Com's Ethernet switch/jack technology, and has been implemented for VoIP.
I've found it to be a godsend for my wireless APs, as I can mount my APs near the ceiling (away from students), and not have to worry about finding an outlet, or having them unplugged by the cleaning crew!
Allows power to be distributed where there's no mains sockets (saves on wiring), but also has the potential to damage hardware if a short in the cable occurs.
If they just made it a little thinner and lighter, we could have wire Remote Control Airplanes! Or even Boats!
We have always had trouble using power lines for sending and receiving data not beacuse it is impossible but because our current power lines were never designed to carry data.
Imagine a merging of the current ethernet and power line standards, you could potentially solve the last mile problem and and at the same time open up new backbones.
you talk about ip over mains.
the story is about, Power-over-Ethernet.
now compare those two real hard, and maybe you'll notice that their not the same
..."Ethernet/Internet over Power Lines" like was mentioned in this previous /. story ???
yeah.
not if someone smarter than you designed the fucking card, asshole!!!
I think you're talking about net-over-power. The story is about the reverse, power-over-net. Neat, but I'm not in favor of accidentally frying my ethernet card by plugging int he wrong cable. Hope they use a different connector!
Check out my eclectic infosec blog at InfoSecPotpou
I can smell burning...
Jon
OK this is a good idea from my perspective. I have used Cisco IP phones w9ith this and they work great it's a LOT easier than a UPS for every IP phone (look at a sales guy and try to explain why the phone died when they power took a hit phones need to be reliable) I have used it with 3com AP's again it works great and makes it easy to stick the AP on the drop ceiling and other hard to reach places PoE again can provided needed UPS power to the AP it also has the side benifit of the AP isn't up and running unless the network is plugged in (I have seen it happen it's not pretty)
I'm waiting for a laptop that can suplement/charge itself over PoE I have a subnotebook that only draws 14 watts charging PoE is close to that possibly enough for a trickle charge. It would seem to be a cheap addon to a laptop ethernet. A lot of people in offices hook laptops up to PSU but leave them on the wireless because it's easier this could make a one cable solution. I can see a whole line of terminals as well for POS applications. In reality on a lot of things this could replace the charger for small devices like PDA's and hook them up to the network at the same time.
Now it seems to be incompatable with GigE over copper since that uses all 8 wires.
No sir I dont like it.
- why no links on X10 ?
Because they are misinformed. They are thinking of X10-the-company, which is notorious for pop-under ads. But what they really mean is X10-the-protocol [scroll down a bit for a good introduction], which is used by many companies.
- which maxim is obvious ?
Maxim is a "gentleman's magazine" that has been pushing the limits of how much semi-porn you can include without getting banned from shelves. Recently this and competing magazines went too far for Walmart.
bp
Now all we need is an adaptation of this norm to Wireless networks. 802.11af anyone ?
They are talking about power over ethernet not the other way around... i.e. put 48V or whatever on the same wires that carries the ethernet signal not putting IP packets on your wall outlets.
If you want wireless power, just hook up a good ol' tesla coil.
Wake me up when they invent wireless power.
:)
No, I don't. Care to provide information or just hide the issue?
to implementing power over TCP/IP.
Read the RFC Here.
Alcohol, Tobacco and Firearms should be the name of a store, not a government agency.
The parent is a troll. Please read the topic before you post. This is not about Ethernet over 120/220/240V power from your utilities. This is about carrying power on your CAT5 cable.
... 12V +/- 5% at 500mA maximum.
At DEC, we had an interesting time trying to figure out how to get all of that UL approved, etc., since it was the first time we'd fielded a device with that kind of external power arrangement.
But, it was on one of the 4 twisted pairs in the
Ethernet Transceiver Cables.
The H4000 Ethernet Transceiver had an onboard DC-DC converter to bring in the +12V and supply -5V and -10V to the transceiver itself, so that it could suck current out of the coax.
Ah, those were the days...
here is a link to TI's PDF datasheet only $1.25 in qtys of 1000 for the device side, much cheaper than a wall wart
Free cell phone tracking
So when can we have power over bluetooth? ;)
Sweet ! Now you can get ethernet over power over ethernet !
...but the only power that's going over my network is the *p0wer of pr0n*.
-- I love the smell of Blue Screens in the morning.
Imagine getting a kilovolt (at a kiloamp) back from a web site that's being slashdotted.
Or better yet. Imagine sending THAT as a response to some Spam.
That would take care of the problem PDQ.
MSBPodcast.com The opinions expressed here are my own. If you don't like 'em... Think up your own stuff.
While overstated, I wonder what the power safety capabilities are in some of the already-available implementations of this.
I'm not as worried about shock, but about unintentional shorts burning out switch ports or misplugged equipment. It'd be awesome if there were software-resettable breakers on the switches so that you wouldn't lose line cards. I had the misfortune of accidentally shorting a couple of Merlin phone system ports and those ports are dead, dead, dead forever.
I also wonder what it does to existing wiring codes and cable plants if any significant power starts to become present on data cabling. It'd suck to become dependent on this power only to have data cabling drops become more costly due to tighter code restrictions on where they can be placed.
Step one. Add full wave bridge rectifier and filter capacitor to WI-FI card antenna. This charges the batteries in your laptop. ;>)
Step two. Make simple mod to AP to bump up power using discarded microwave oven magnetron.
It works great; I can surf all day without plugging in. I will post instructions when I get back from the doctor. It has been cloudy all week but some how I have gotten this wicked sunburn.
No way am I electrifying my dongle again.
Fool me once, shame on your. Fool me the fifth time, shame on me.
It's 10 PM. Do you know if you're un-American?
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."
Commas, periods, and semicolons, oh my!
Commas, periods, and semicolons, oh my!
Commas, periods, and semicolons, oh my!
Chuck Norris: Socialism == a thousand years of darkness.
I'll wait for the wireless version that comes out for 802.11b..
Power of wireless ethernet now that would be awesome! Then people would really have to secure their access points or people could borrow power from their neibors! *lol*
Nick
Encryption: I may not agree with what you say, but I will defend your right to encrypt it...
*yawn* need to wake the hell up *lol*
Nick
Encryption: I may not agree with what you say, but I will defend your right to encrypt it...
Power over 802.11x... Oh, and remind me to buy lead pajamas then too...
That would only happen into a one-ohm load. Hopefully your system doesn't have such a low load or it'll drain 25W at 5V. Mind you, if you hit it with 1kV, you might find the molten metal would give your the low resistance path you need...
I was just looking at this item from Dlink for doing just that sort of thing. A quick search shows it's only around $50 on the 'net.
"I can't give you a brain, so I'll give you a diploma" - The Great Oz (blatently stolen sig)
Would be great for my Palm Tungsten C (-:
Seriously, this should be possible in another way: put a magnet in the Palm, have a huge magnet somewhere in the room that changes its poles rapidly which makes the Palm magnet turn... voila!
Or is that far-fetched?
The hot-swap chip is required by the standard and handles unitentional shorts. From the data sheet: "Provides Safe Hot Swap for +10V to +65V Power Supplies". This also 1) limits maximum inrush and 2) limits steady-stage current to 1) avoid "drooping" the supply voltage and 2) handle faults on the secondary (e.g. 6 V) side. I haven't looked at the standard recently, but there are supposed to be limits on the supply (-48 V) end to handle faults there. The reasons -48 V is used are it is very standard in telecom so low cost parts available for DC/DC converters and it is less than +/- 60 V which is the limit for "low voltage" in existing wiring codes.
I believe anything under a certain voltage is exempt from being subject to the electrical code. 35 volts seems to spring to mind. It probably varies from state to state. There may also be amperage restrictions.
As far as protection goes, a simple thermal breaker would work, and be self resetting.
I've had enough abrasive sigs. Kittens are cute and fuzzy.
No, I want my power delivered by 802.11x / / /
_____
\
\
____O____
\ / \
.\/ \/
:-)
The Linear typical app seems to be much smaller, with fewer external components because it's actually optimized for the application.
The Maxim chips appear to be generic hot-swap IC's not optimized for power-over-ethernet. Using slashdot is an interesting way to publish an app-note and get some publicity.
Just download IEEE_802.3af_FULL_REAL_WORKING_VERSION.exe
-]Phreak Out[-
or does the synopsis for this article look like it was written by some lame AOL script kiddie?
No I am not trolling, I think we should edit these synopsises before they go live.
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
lets hope that wireless power is next ;)
Ma didn't need no stinking wires. She yelled at us so loud and rubbed us against the walls so hard, the light in the bulb lasted untill the next evening.
You had light bulbs? We had to eat supper only lighted by the static from rubbing our cat.
I want to surf the web on my wireless handheld and have it recharge.
Posted by Hemos on 15:00 19 May 2003
from the like-ma-no-extra-wires dept.
Must mean that ma is high strung enough as it is, what with the dot com crash, 9/11 and everything.
Or that we like "ma" with no extra wires, i.e. nekkid.
"How do I look pop?"
"Perf'ek, ma!"
[OT RANT]
I wouldn't have cared to post anything if it wasn't for M1 on parent. The FAQ says "Karma is not your dick size." Huh? Right now I have "Karma: Excellent", so I guess the FAQ needs updating.
[/OT RANT]
Irene KHAAAAAAN!
www.splashpower.com, not exactly a long distance solution, but it's the first step and is great for PAN's
X10 the protocol was developed by X10 the company, which still owns a number of patents on it.
So sadly, www.x10.com is the official site for the x10 protocol (although you can't find any details on the exact protocol these days.)
retrorocket.o not found, launch anyway?
I can't wait until they update 802.11b to include this.
It seems like an integral part of this standard is current limiting circuitry that will prevent shorts from doing damage.
At least the Maxim ICs there appear to have a number of safety features.
retrorocket.o not found, launch anyway?
Simple. Properly designed hotswap hardware should have current limiting circuitry built in.
:)
Similar to a fuse/circuit breaker (Good to have those in there too!), but they don't permanently shut down.
I work in an RF power amplifier development lab - Trust me, current limiting power supplies are a reality and they are a truly wonderful thing. (Yeah, we short out a lot of stuff here.
retrorocket.o not found, launch anyway?
I'm currently using the POE hardware from HyperLink. Works like a champ with my Netgear 802.11g AP.
I have been selling these at BrightNoise for use with IP enable cameras and APs for some time. They work great. In fact Axis is re-badging them as their own.
They save you a ton of money on electrical costs and general hassle. There is a web enabled version that allows you to power cycle individual ports as well as set critical ports for UPS use.
Si vis pacem, para bellum! For evil to succeed good men need only do nothing!
3com's IP phones support doing this, as does their MBX telephony hardware.
/. noticed ;)
I went to a 3com IP phone training session about two and a half years ago in which we learned to set up their telephony boxes. Most of the guys there were telecom installers, guys who'd been servicing telephone equipment for years but hadn't used computers more than the average guy, so I saw things from a different perspective. Neat hardware, quite flexible, and ran some form of *nix, but configuration was through a tastefully designed browser interface.
Anyways, the guys running the show said that all 3com Ethernet hardware (yes, including NICs) is compatible with the power-over-LAN features, but non-3com devices required a "filter" adapter to prevent frying the circuitry.
It made sense in that it was easier to simply provide cat5 and use 3com hardware than to worry about powering all of the phones (do we have enough outlets/power strips/whatever?).
Win for the business: simple configuration and deployment.
Win for 3com: It's easier for the consumer to use _all_ 3com hardware than to worry about filtering all ethernet devices.
Neat stuff, in development 3+ years before
Somebody get that guy an ambulance!
One of the nicest apps of PoE is definitely small, dirt-cheap, semi-disposable network appliances, which wouldn't be as affordable if they had to include their own power supply. Those would definitely include sensors of different kinds, protocol bridges (e.g. lately I've been thinking about migration paths from closed, DRM laden digital audio interfaces to open ones based on standard 100Mbps Ethernet) and the like.
But perhaps the nicest application I can come up with are miniaturized throwaway remailers built on cheap microcontrollers with integrated Ethernet hardware. The cost of a fully functional (if limited capacity) mixmaster might well be pushed into the range of dollars, suddenly making it possible to distribute hundreds of remailers into unsuspecting networks around the globe. If they're picked up, so what -- the cost is negligible. Up till now the problems have had to do with the level of integration required, power supply trouble and ease of physical detection. PoE solves two out of the three problems in one fell swoop.
decoy
I have a Soekris net4521, and it works great with PowerDsine's PD 6001 (part of their PD 6000 mid-span series).
They (PowerDsine) have been doing 802.3af since its earliest drafts, and it's been working as designed.
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
HIV Crosses Species Barrier... into Muppets
The Gibson Magic spec included 802.3af support - that's how they're getting the power to their new Les Paul guitar that sends out an 24/96 audio per string. Makes sense - it's bad enough having an RJ-45 socket on your guitar, even if ruggedized, you don't want extra power cables too...
(this is not a
Does this mean that RFC 3251 is just around the corner?
RMN
~~~
"I can just see it -- I fry myself inserting the Ethernet cable in the card. Instructions read: before inserting, go to your power panel, can shut off the circuit breaker for your computer and then... "
I don't see why this is a troll. I got shocked by plugging a phone line into a modem once years ago. Felt pretty stupid.
"Derp de derp."
Now it seems to be incompatable with GigE over copper since that uses all 8 wires.
The power supply seems to use BOTH halves of each pair for ONE power wire - the "common mode" - allowing you to also use the differential mode for the signal.
You need a center-tapped transformer to inject or extract the power if you're using the pair for both signal and power. Capacitors are adequate if you only want the signal. (Note that transformers inserted into a GigE run to inject/extract 20ish miliamps will have to be something pretty special, or they'll shorten your range or just kill the link.)
If your device is already transformer- or capacitor-isolated (and doesn't have the common mode tied anywhere - except maybe by a LARGE resistor) - you shouldn't see any smoke if you plug a legacy device into a powered link. But there's been a LOT of devices built, and they may not all have been designed well enough to handle one of the pair hanging 50ish volts from both the other signal pair(s) and protective ground.
By the way - using the common mode of two balanced pair to provide a third balance pair - for power and/or signaling - has been around for a long time. It's called "phantoming". The phone company used it back when phone lines were strung with individual wires. (Miles of wire installed and maintained outdoors have ALWAYS been more expenisve than transformers.) You can also phantom on a pair of phantoms. So with N = 2^M wires you can get N-1 effective balanced pair rather than the N/2 actual pair - nearly doubling the number of available circuits. (Of course it causes trouble for a LOT of signals if ONE wire goes bad...)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Uh guys this waas done way back buy a under rated man name Nicola Telsa. Check it out it's some cool stuff.
They have been doing this for a couple years now. Why is an update on the standard news?
Is this going to work with cheap installations which are already using the extra pairs in Cat5? RS sell a splitter / combiner which (as a last resort) lets you use the "spare" pairs in an existing 10/100 base-T run to run a parallel 10/100 base-T connection.
It MAY work - or at least not fry it. And it will probably continue to work if you don't want to use the power. But you'll need another device to inject/extract power on the "second line" if you want to use it for both power and signals. And the device will need to be the "series transformer pass-the-signal" type, rather than the cheaper "tie the wires together and run 'em to a power supply" type.
I HAVEN't read the $67-member-price draft (that nobody seems to have summarized to Slashdot yet - thanks guys...). But judging by the allegedly-conforming implementations that HAVE been linked, the standard seems to involve:
* a -48 volt supply and its return
* each power supply wire using BOTH conductors of a pair.
* (It's not clear whether the standard only talks about using the "spair pairs" or explicitly addresses phantoming onto working signal pairs.)
Some of the equipment is set up to use the two "spair" pair as the power wires, just tying them together. Other equipmet has a pair of transformers to use a pair-of-pair for BOTH signaling and power, via center-tap "phantoming".
So the cheap connector that just brings out the second pair-of-pair for a separate ethernet run will
I can smell burning...
On any device that didn't properly DC-isolate both the signal and "spair" pair for >50 volts, combined with a power injector that doesn't current limit, quite possibly. Ditto if somebody wires a jack wrong and, say, swaps a conductor from a pair supplying the -48v with one from a pair supplying the 48v return path.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
For low power ethernet cameras. They first started making them three or four years ago, and they work great.
IQeye Cameras
We had 220V on our ethernet cables for months! Turned out we pulled two cables through a hole that was maybe a little TOO narrow... The PC's didn't mind though, the network admin was a little more "shocked"...
10 ?"Hello World" life was simple then
girl is naked, take a movie
girl is looking, picture cutie
you buy thing from pop up banner
you get wallet, purchase camera
we must destroy x10, we must destroy all internet ads
we must destroy x10, we must destroy all internet ads
window pop up on the screen
taking control of my machine
making all internet user insane
x10 profit goes down the drain
girl is naked, take a movie
girl is looking, picture cutie
you buy thing from pop up banner
you get wallet, purchase camera
we must destroy x10, we must destroy all internet ads
we must destroy x10, we must destroy all internet ads
the economy failing is x10 fault
popping up window is computer assault
window popup again and again
only solution is crush x10
we must destroy x10, we must destroy all internet ads
we must destroy x10, we must destroy all internet ads
we must destroy x10, we must destroy all internet ads
we must destroy x10, we must destroy all internet ads
- lyrics to "WE MUST DESTROY X10" by KOMPRESSOR
Who uses 44+ volts DC for anything? It seems like just going with 5V would be better, and less likely to fry stuff with shorts in the cable; if a 5V line shorts to a signal line, the signal is held high, and your cable just doesn't work, without taking anything out of spec. Of course, 350mA at 5V is too little power, but increasing the current a bit would be reasonable with a 10-fold decrease in voltage.
What exactly are they planning to power with this? Embedded devices and PDA-level devices (like wireless access points) don't need nearly that much power.
(I have personally modified a cheap hub to let me run 5V over ethernet, so I know it's reasonable; it works fine for essentially any device that you might run off of batteries if you could keep the batteries charged)
Power over ethernet over power over ethernet over power over ethernet over.....
With all them layers, you press the light switch and, after 5 seconds (unless you're a low ping b******), it finally turns on.
Hello /.!
Has anybody seen/tested/used AXIS's Power-Over-LAN equipment/midspans/adapters?
What are your 2cents on them?
Cheers, Paolo :-D
Paolo A. Gallenga System Administrator pgallenga@email.it
Once a wireless version is released, you'll have my attention!
I don't want to sound troll. But this thing (ethernet over power lines) is freaking out ham radio operators all over the world. Look for example here. And based on the law "if the shit can happen it certainly will" this will bring EMI problems to all equipment that is connected to or in the vicinty of the jack in the wall. Your TVs your stereos your computers etc.
Besides have anybody of had to deal with power companies? Do you really want THEM to provide your internet connection? Or even being involved in providing one.
Time and time again it returns (and will keep returning) to the simple truth. You need an adequate infrastructure to provide high speed Internet.
In the beginning of DSL I kept hearing a lot of strange things going against physics. Such as UTP (unshielded twisted pair) is better than coaxial cable etc. Well guess what, being entirely untrue this is not the end of the story. The pair that runs the phone line in your home/appartment is not even twisted, its flat (and it's CAT 3 most of the time to the central office).
It took huge amount of money to put power lines, phone lines and CATV into every home. And the companies that were doing that were cutting costs like crazy. Which means that nobody ever thought that someday it will be used for something else besides its initial purpose. And again based on the law I mentioned in the beginning it will be probably the worst case scenario for anytiing else. In case of DSLs that certainly is crosstalk and EMI and also distance. For example in my case no DSL provider does even want to install it for me citing that I am too far from central office.
Personally I think the interrim winners of all this will be the cable companies. Just because the people who decided to get broadband internet access usually go all the way once they've set to have it. Most people I know who started with DSL eventually just switch to cable modems. But eventually every body will lose because again CATV was not intended for anything else. (Just an example untill recently CATV equipment manufacturers were refusing to use multilayered PCBs because it was "too expensive"). So this is it. People just keep their heads in the body cavities of their choice and keep selling each other a snake oil.
On the other hand. It would be actually nice (especially with current situation in tech sector of economy) if we'd start laying fiber to the home and/or build sane infrastructure for wireless access.
Just my $0.02
- Back off man. I am a scientist
...mention of the BOFH!!!
Another relevant fave found here.
The whole shebang.
I'm done with sigs. Sigs are lame.
And, to get really secure power, that is verified to come from your chosen site, can you encapsulate it into a IPSec tunnel? :)))
-- Sig down
"X10-style (no link, u know why)."
No I don't, guessing it was a spat sometime back I did search the archives. Other than the sheer obviousness, why no link?
I'd go on a Vegan diet but the delivery time from Vega is too long. --brownkitty
Now can they do it over 802.11b? My laptop is running low on juice and I don't feel like coming in off the back porch to recharge it...
The submitter put SO MUCH editorial in his submission that no further comment was needed.
Now you know how to stop the editorializing, stop bitching about it and let the rest of us enjoy it.
http://pcblues.com - Digits and Wood
check out otcwireless.com. they have what they call a DC injector that provides power over ethernet to their outdoor WiFi AP's as well as their outdoor proprietary wireless networking solution.
I've looked into those very jacks with an existing home installation I have... problem is, I want to future-proof the place as much as possible by having a clear upgrade path to gigabit ethernet (over copper... no way I'm crawling around in all the fiberglass to rewire the house with fiber).
PoE uses the unused pairs (in regular 10/100Mb ethernet) to provide the juice... gigabit over copper requires those pairs to carry data.
Sooo.. you can have PoE and use it to power those jacks (a very sexy idea, I must admit), or you can ditch PoE for the sake of future upgrade to gigabit.
I don't see a way they can coexist... anyone care to correct/enlighten me?
Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes.
So which is it, phantom power, which has been around the audio world for practically forever, or did somebody finally notice that for years now people have been installing (and paying extra for) 8 wires to do the job of 4?
I see even classic Slashdot is now pretty much unusable on dial up anymore.
Much smoke and brilliant flashes.
Got time? Spend some of it coding or testing
Some contributors have expressed concern about damage to existing equipment etc. This should not be a problem. The standard defines a method for determining whether a node is PoE-ready, and only applies 48V to those nodes. Other nodes just see the "discovery" signal - a current-limited voltage in the 2-10V range. The standard also includes plenty of other protection mechanisms - current limiting, power limiting, disconnecting when the load changes. The power supplies at the user end are specified as isolated, with a 1500V isolation barrier. And the IEEE engineers, who spent 4 years slaving on the technical aspects of the spec, conducted extensive tests with legacy equipment to ensure power could not be inadvertanty applied. I'm putting together a web site on the technology - see www.PowerOverEthernet.com (early days yet) - there is an introductory article at http://www.poweroverethernet.com/articles/000008.h tml - contributions to that site are welcomed!