Possible uses for Power over Ethernet

jsailor writes "Power over Ethernet allows devices to draw power from the Ethernet cable they use for networking. Power is provided by the LAN switch (end-span) or an intermediary device (mid-span). The current spec. is 802.3af and was covered on slashdot before. It provides approximately 13W at the end of a 100 m cable and is commonly used for IP phones, wireless access points, and increasingly security cameras. The technology saves costs associated with running power to the odd locations access points find themselves in and allows IP phones to be moved around with out carrying a power brick. The industry is considering a new standard that would provide up to 39W to a network device. Bizarre uses include electric razors. "

Comments

Easy enough,

[00null00]

But isn't it time for power over wi-fi?

Re:Easy enough,

[Anonymous Coward]

I'd much prefer power over BPL.

Re:Easy enough,

[Vectorferret]

Tesla (who worked with Edison on early electric devices) wanted to transmit electricity wirelessly. Edison ruled it out because you couldn't charge for it that way. It's a good thing Edison won out, as to get enough electricity to power anything useful into the air over any real distance would be a huge cancer risk.

Re:Easy enough,

[xpyr]

Obligatory bash quote, see bash

harm_: today this one lady got pissed off cause we dont carry i quote wireless power supplies
ogregasm: a what
harm_: thats what i said
harm_: maybe you want an adaptor for a wireless router o rsomething??
harm_: shes goes no no i read online about this i wannit i wannit :harm_: then she got pissed when i told her that kind of technology doesnt exist
ogregasm: heh :harm_: i tried to be nice but it got to the point where i was like"get back to us in 30 years"
harm_: "once we attain the secret of positron deflector shields, wireless power supplies shall become a reality"
ogregasm: why bother being that much of an ass to the poor woman
harm_: well shes the one who got all up in my face asking for the store manager
harm_: i told her he had just teleported to a corporate meeting in tokyo

Ah gotta love bash :)

Re:Easy enough,

[Ignignot]

This is rated funny, but Nikola Tesla was working on something like this for much of his life. The Wyadcliffe (sp?) tower is just the biggest example. Go check it out on wikipedia like you do for everything else.

Re:Easy enough,

[jdray]

For that matter, everyone doing work on Solar Power Satellites would be interested to know that this sort of thing is impossible.

Re:Easy enough,

[Anonymous Coward]

Ahh, Wikipedia, the cause of, and the solution to all of life's problems.

Re:Easy enough,

[pronobozo]

who can say rdif

Re:Easy enough,

[Anonymous Coward]

I believe it was J. P. Morgan who pulled the plug on Tesla after he learned that Tesla had no plan for billing people for electricity usage.

Re:Easy enough,

[mrogers]

I've played C&C Red Alert - there's no way I'm having one of those things in my back garden.

Re:Easy enough,

[PHanT0]

I prefer the C&C Tesla coils to shock my ememies.

Re:Easy enough,

[chgros]

The Wyadcliffe (sp?) tower is just the biggest example. Go check it out on wikipedia like you do for everything else.
From your very own link:
Wardenclyffe Tower

Re:Easy enough,

[Ignignot]

That's a tesla coil, completely different than what I'm talking about. However, you do have several in your house. Any CRT's use them, if my memory serves correctly. Not particularly dangerous. The most dangerous electric appliance in your house is probably the toaster or hair dryer.

Re:Easy enough,

[saider]

It's a good thing Edison won out, as to get enough electricity to power anything useful into the air over any real distance would be a huge cancer risk.

Please provide some references for this. I did a paper on this topic about 6 years ago and I could not find one study that provided a link between power and radio frequency radiation and cancer.

What I did find was a lot of people who wanted to blame someone for their ailments. I read several complaints and they all basically read "there were no carcinogens found in the soil/air/water. A percentage of the people all lived close to power lines. Therefore the power lines must be at fault." From what I understand not one of those arguments held up under scrutiny.

Re:Easy enough,

[timster]

As I recall the whole "power lines cause cancer" thing was an example of irrelevant correlation. Turns out that statistically it tends to be poor people living next to high-voltage power lines and poor people have higher cancer rates for all sorts of other reasons.

Re:Easy enough,

[FireIron]

No lie, years ago when Apple came out with IR keyboards and mice for Macs, there was this column in MacWeek where the columnist got all torqued off that there was no wireless power for the Mac. Seems he wanted his Mac to just kinda hang out in the middle of his desk with no unsightly wires or cables anywhere in sight, and he was annoyed that Apple wasn't catering to this need.
I should have clipped that column, it perfectly captured my personal stereotype of hardcore Mac users.

Re:Easy enough,

[the pickle]

You do realise that RF is nonionising radiation, right? And that *ionising* radiation is required to cause the mutations in DNA that lead to cancer, right?

Just checking.

p

Re:Easy enough,

[barronVonBackstabber]

Almost there with RFC3251 just need to implement it ;-)

Re:Easy enough,

[GoRK]

Probably the toaster - Hair dryers all tend to have GFCI devices on the power cords these days while most toasters still don't. You will zap yourself pretty good if you drop a hair dryer into a bathtub still, but you probably won't die anymore... Unless your house is totally miswired!

Re:Easy enough,

[Anonymous Coward]

Anyone that drops a toaster into the bathtub is obviously trying to kill themselves. Why would toaster manufacturers want to abandon the suicide market?

Re:Easy enough,

[saider]

Another thing to keep in mind is that household power lines, although carrying a lower voltage, are much closer, and therefore contribute more to the local electric fields.

Re:Easy enough,

[pisces22]

That's been done. It's called lightning!

Re:Easy enough,

[Moofie]

Well, I hate to bust on you too much, but Apple never released IR keyboards and mice. They had IrDA adaptors on some computers, and remote control sensors on some computers, but kb and mouse are ADB or USB or BlueTooth (at least on anything newer than a ToasterMac).

Re:Easy enough,

[Lord d'Eath]

I can say "RFID"....

Re:Easy enough,

[Anonymous Coward]

Another thing to keep in mind is that eletrical fields generated by neurons in your brain are larger (since they are much, much closer) than fields generated by power lines.

Re:Easy enough,

[sexecutioner]

OT but mildy related:

True enough, but mobile phone frequencies are non-ionizing as well and there are heaps of people that think these give us cancer.

RF has a heating effect as the energy is absorbed by the water molecules in our body. This is how a microwave oven cooks food.

Tests have been done to look for the heating effect caused by mobile phones but none has been found, the transmitters are not strong enough.

Can anyone explain why people think mobiles cause cancer?

Re:Easy enough,

[mattyrobinson69]

my pairents got a new computer a couple of months ago. Its got a wireless keyboard and mouse, but the keyboard was playing up. I went round and had a look. I said "batteries might be dying", my mum said "What? its got batteries. GEOFF!!! (my dad) take this keyboard back, it needs batteries.

old people eh?

Re:Easy enough,

[ocularDeathRay]

it is my understanding that the reason microwave ovens work is that they operate at some sort of resonant frequency of the water molecules. I don't think it is RF in general. granted this was from a high school chemistry class so it may be oversimplified.

Re:Easy enough,

[Anonymous Coward]

And your understanding would be wrong.

Microwaves work simply by pumping a shitload of energy into something that will absorb it. It's not about resonance or any of that nonsense--because water resonates somewhere around 11Ghz. It's really no different from using visible light or infrared, except that the chamber is designed to bounce the high frequency stuff around better (more efficiently) than could be done with either light or infrared--both of which would easily escape the window, and would cause more heating of the aluminum cage.

I'm not exactly sure why they chose 2.4Ghz to use as microwave frequency, my best guess would be that food tends to absorb it better than other frequencies, or that it was simply easier to make that way.

Re:Easy enough,

[Anonymous Coward]

edit: microwaves are designed to bounce low frequency EM radiation better. My bad.

Re:Easy enough,

[Long-EZ]

Microwave ovens operate at 2.4 GHz, same as the clock frequency in my laptop PC's P4, and the same as many wireless devices such as cordless phones and 802.11b wireless networking. Cell phones work at slightly different frequencies, but they're close enough that similar issues are involved.

I don't think most people who worry about RF are concerned with localized heating of body tissue. I think most people are worried about possible mutagenic characteristics of the magnetic field. There has still been no proof of this in low power devices such as cell phones or wireless networking cards, and a lot of recent studies have tried to find such a link. But I think we'd all agree that staying warm by standing in front of a distant early warning radar transmitting antenna in Alaska is not good for you. BTW - This is a real example. A friend was stationed there in the late 1960s (before we all had microwave ovens) and the radio engineers totally freaked when they saw the guards doing this while on guard duty.

Re:Easy enough,

[ScrewMaster]

The principle of the microwave oven was supposedly discovered by an early radar engineer noticing a thoroughly melted candy bar in his pocket. A lot of radar technicians ended up with cataracts before the phenomenon was well understood, because the cornea is capable of absorbing microwave radiation but isn't able to disperse the heat well since there is no significant blood flow around it.

Re:Easy enough,

[jmg1195]

Tesla already had that idea, but no one listened. http://www.unmuseum.org/tesla2.htm

Re:Easy enough,

[bobbitt]

Yeah... reasons like "they live next to power lines."

Re:Easy enough,

[Anonymous Coward]

someone that died on one won a darwin award.

Re:Easy enough,

[lars_stefan_axelsson]

Can anyone explain why people think mobiles cause cancer?

Because heating while being the most straight forward concern, isn't the only one. Tests on a rat model here in Sweden seems to indicate that mobile phone radiation could make the blood-brain barrier more permeable to the protein albumin. While this doesn't cause cancer, it does cause brain damage. And brain damage was observed in the rats. No-one is quite clear why, albumin wasn't thought to be that dangerous, but a hypothesis is that it takes heavy metals with it from the rest of the body.

So in short the jury's still out on the subject. It's as you said: if heating was the only possible mechanism in which EM fields could affect humans, we'd be set.

Re:Easy enough,

[penthouseplayah]

Quite often you'll hear somebody blame something for adding an added risc of cancer. The fact is that statisticly if you have 20 communities of 3000 people the chance of NOT finding an increased risk of something (cancer, kidney- ,heart- whatever dicease) is something like 1:1 000 000+

Now remember how many 3000 people communities lies out there in the entire world! No wonder high powered electricity got the blame more than once. They're big, ugly and not natural.

Re:Easy enough,

[MikeFM]

What?! I like to live in my bathroom. It's got a tv, a microwave, a little fridge, and a laptop. What more could I need? If toasters were safer I could keep it next to the tub!

Re:Easy enough,

[0x0000]

About 8 years ago I heard that the military/spy agencies were using an audio bug that demodulated its power from an RF field that was transmitted to it. Low power, very small application of some of Tesla's work. So yeah, I would say it's past time for power over WiFi...

Re:Easy enough,

[0x0000]

esla (who worked with Edison on early electric devices) wanted to transmit electricity wirelessly.

As I understand it, Tesla did transmit electrical power "wirelessly" using RF. Lit up a bank of stadium floodlights from a mile away, or something.

He wanted to apply those principles to the (planned, at that time, i'm sure) power distribution "grid", which is evidently where the disagreement with Edison came in. I believe Tesla is also responsible for the fact that the power company isn't still trying to distribute DC...

to get enough electricity to power anything useful into the air over any real distance would be a huge cancer risk

This statement is patently false. It is the 60Hz EMF that exists now that is a huge risk, although it is arguable whether or not the risk is "cancer", per se. There have been a lot of studies done on the effects of EM on organisims; it became quite clear that the relatively sparse RF power fields are less damaging to organisms than the extremely dense low frequency (60Hz) fields that surround the wiring in buildings.

Strangely, the EM associated w/ ~200V 50Hz AC (what they have in Europe) is apparently less dangerous than 120V 60Hz, though. Something about the resonant frequency of cells, or something ...

Re:Easy enough,

[0x0000]

although carrying a lower voltage, are much closer, and therefore contribute more to the local electric fields.

It is the current determines the EMF, not the voltage. With sufficient current, the field will cover the distance between the transmission line and the home at the base of the tower.

There is a voltage/current conversion that is the reason high voltage lines are high voltage.

In any case, electro-magnetic flux can be measured, and the field from high-voltage will combine with the field generated by the house wiring.

Re:Easy enough,

[sarabob]

But of course, they could get some free electricity if they were clever...

Re:Easy enough,

[AstroSurf]

I could not find one study that provided a link between power and radio frequency radiation and cancer.

That's because it would be bad for business. You'll find those studies in Russia, where they're much more strict about how close people/power lines can be.

Just like you're not gonna find any studies that say that cell phones cook your brains. It would be bad for business.

Always remember: It's not really science until an American scientist gets paid to make a pronouncement.

Re:Easy enough,

[AstroSurf]

statistically it tends to be poor people living next to high-voltage power lines and poor people have higher cancer rates for all sorts of other reasons.

Right you are! The primary reason is that, statistically, it's richer people who are able to buy residences that are remote from environmental hazards.

Luvey: "Oh, Thurston, I want to live beside an airport." Doesn't happen.

Re:Easy enough,

[jbridge21]

You do realize that ionization is not the only way that RF can affect the body, right? There's your basic heating and then there's this:

microwaves open up the blood brain barrier

Just because we know that ionizing radiation definitely causes mutations which can definitely cause cancer, doesn't mean that there aren't other possible routes.

Re:Easy enough,

[Anonymous Coward]

Don't tell me, let me guess: you got your history education from the back of cereal boxes, right?

Tesla *invented* the AC motor.

Yes, he wanted to transmit electricity wirelessly.

The argument between Edison and Tesla was about AC versus DC power distribution - Edison waged a huge PR war claiming that AC was "dangerous". And it's a good thing that Edison *LOST*, because otherwise electricity distribution would be too expensive.

It was J.P. Morgan that didn't want wireless electricity to happen (because then you couldn't charge for it.)

Re:Easy enough,

[timster]

Grin, of course that isn't an "other" reason. And someone please mod the grandparent down -- it's a 3 at most and I don't need the karma.

Re:Easy enough,

[Anonymous Coward]

sounds like either a prison or a dorm room...

excuse me... "Residence Hall"....

Electric Razor?

[Anonymous Coward]

RoIP. Rash over IP?

Seems Kinda Weird / Wired

[engywook]

I guess there must be a market for this somewhere. It just seems to me that if you can manage to run a wire to carry the Ethernet networking signals, it should not be all that much more difficult to run some power at the same time.

Now, on the other hand, if this were providing power over an 802.11b/g connection, I'd be asking where to sign up!

Re:Seems Kinda Weird / Wired

[Enzo the Baker]

Depending on the safety code for the area, you probably need an electrician to run power. You probably have to have conduit, junction boxes, run it back to the circuit breaker (which may be in a different place than your network switch), etc. If it's just Ethernet cable, you can probably have just about anyone run plenum rated cable wherever you want, without the extra hardware.

So for new construction, it's probably not a big deal. But for adding new devices to an existing facility, it could be a lot easier/cheaper.

Re:Seems Kinda Weird / Wired

[Anonymous Coward]

There is far more regulation re the running of electricity, plus, where I work, the electrical is a mess since the building is very old and has served several different manufacturing industries in its life. It can be a real trick to get a new box put in. OTOH, its trivial to run another drop for networking.

Re:Seems Kinda Weird / Wired

[cafn8ed]

I don't know much about the underlying technology, but if the ethernet-delivered power is DC, then it could save some space, weight, and efficiency on the part of the electronics to not have to convert the AC current to DC before using it. In other words, no transformer brick needed for the device.

Re:Seems Kinda Weird / Wired

[runningduck]

I would love for my TV to run on PoE. Then if my TiVo multicast channels [TV] life would be perfect.

Re:Seems Kinda Weird / Wired

[RetroGeek]

Depending on the safety code for the area, you probably need an electrician to run power.

Normal voltage power, yes.

But 12 volt low current does not require the same rules. Anyone can run wires for a doorbell, even though it carries 12V DC.

So co-running a low voltage wire beside the LAN cable should not be a problem. If it is, then running the LAN cable would also be a problem.

Of course you need to set up the AC->DC converter and properly fuse it...

Re:Seems Kinda Weird / Wired

[NardofDoom]

I don't trust most network admins to run Ethernet, and you want me to let them run 120V power cables, too?

Re:Seems Kinda Weird / Wired

[mozingod]

It would be a pain, trust me. A buddy of mine works for a company that provides WiFi access in hotels, and they needed help setting up a large one this past weekend near Sandusky, OH. Because of the thick walls in this older place, they needed another WAP every 6-8 rooms to get good coverage.

There were only one or two recepticles per floor (in the ceiling tiles), so power was at a premium. They got the clever idea of taking a biscut with two keystones, crossing the green/orange pair to the other keystone for data, and tying the WAP's severed power cable to the brown/blue pair off the original keystone. We did the same with the other end of the WAP's power inverter near the switch. This way we had an 8 port surge protector where the switch was plugged in, and ran the power over the blue/brown pair to the WAPs. Cable from switch into one port, patch cable from the other port into the WAP for data, and the power cable hung out the back. Cheap and dirty method, but worked great.

Unfortunatley, and the reason I was brough in to help, they found out the brown pair alone couldn't carry the current far enough (past a few rooms) to keep the WAP on for more than a few minutes. We had to convert them all to use both the blue and the brown pair to work right.

Re:Seems Kinda Weird / Wired

[Anonymous Coward]

Different trades ... why hire an electrician when your data guys can handle the low voltage stuff.

Re:Seems Kinda Weird / Wired

[SuiteSisterMary]

Running ethernet through the drop ceiling to a corner, where you mount an AP can be done by some idiot with a ladder and some cat5.

Running electrical wire, on the other hand, requires a licensed electrician, and all sorts of building codes to be satisfied.

Re:Seems Kinda Weird / Wired

[gcaseye6677]

You didn't run 120 VAC through those cables did you? I'm guessing you used lower voltage that was just enough to power the WAPs. Does this pose any problems regarding electrical code compliance?

Re:Seems Kinda Weird / Wired

[mozingod]

We split the power pack from the WAP, so it was only transmitting the voltage the WAP used (don't recall what that or the current was). Damned if I know if it violated the local codes... I was just a wire monkey for the day.

Re:Seems Kinda Weird / Wired

[rcw-work]

In other words, no transformer brick needed for the device.

Transformers are not used to convert AC to DC. Transformers only convert AC to a different voltage AC. The rectifier portion of the average brick (the part that does convert to DC) is very tiny. Often it's only four diodes and a capacitor.

So basically, if you needed a transformer to power a device from AC, you're just completely screwed if you try to power it from DC, unless it was regulated at the right voltage beforehand. Since we're discussing PoE, that would be a giant no.

Switch-mode power supplies are just as efficient with DC as with AC. They are very small and lightweight, and that's what you'll find in most 802.3af-powered devices. However, if you want to keep discussing alternative forms of local power distribution, those transformers also become very small and lightweight if you change the operating frequency from 50/60Hz to, say, 100kHz.

Re:Seems Kinda Weird / Wired

[DLWormwood]

Running ethernet through the drop ceiling to a corner... can be done by some idiot with a ladder and some cat5.
Running electrical wire... requires a licensed electrician...

In other words, this technology is being made to exploit a loophole in the law. A law made to improve public safety.

In the long run, all this will do is encourage politicans (with union or trade association backing, no doubt) to regulate the laying of cat5 since they now can carry a "dangerous" payload.

This is one of those things that's been annoying me about computing since the Internet. The innovation ethic that permeated technology keeps generating inventions that now have genuine and visible social impact. This only leads to increased institutional scrutinity by politicians and industry experts. We technologists are really starting to bite off more than we can chew. I fear for the day when the typical end user will require a licence to use a computer for fear of letting "terrorists," "hackers," and "freeloaders" onto the "Intarweb."

Re:Seems Kinda Weird / Wired

[mazevedo]

I guess when you have about 350 IP phones, 140 cameras and about 13 APs (all of the use PowerOver Ethernet)and about 200 computers, you'd probably prefer to buy 60 Catalyst 3550 than to make all new cabling to support all the powering needs. Let's not include the necessary power "bricks" for all the phones: they're big and each one costs about $40.

Re:Seems Kinda Weird / Wired

[Anonymous Coward]

There is a rather obvious market for this, which an additional power line cannot fill.

1. Use power-over-ethernet to power a couple of LEDs spread evenly over the length of the cable.
2. Make the LEDs indicate traffic.
3. Profit!

Re:Seems Kinda Weird / Wired

[Anonymous Coward]

Power over Ethernet. PoE. OPE. POE. Purity of Essence. Do you realize that fluoridation is the most insidious commie plot to ever threaten our precious bodily fluids?

Re:Seems Kinda Weird / Wired

[IvyKing]

Switch-mode power supplies are just as efficient with DC as with AC.

Switch mode supplies can be made to run more efficiently on DC than AC since rectification isn't required. Additional losses in an AC supply include diode forward voltage drops and ripple current losses in the input filter capacitor. Granted the difference isn't very big.

Re:Seems Kinda Weird / Wired

[jrockway]

As an IT support d00d, I PREY for the day when the typical end user will require a license to use a computer!

What a shame...

[mansoft]

The razor doesn't have networking capabilities!

Re:What a shame...

[Anonymous Coward]

Imagine a beowulf cluster of razors!!! The Mach 3 model could run on 3 Blade servers.

Re:What a shame...

[laard]

Sure it does...

Hello moto...

Re:What a shame...

[Total_Wimp]

The razor doesn't have networking capabilities!

I thought a similar thing the first time I saw one of those little laptop lights that plug into the USB port. Now devices that use USB just for power are extremely common and some are quite creative and useful. I love recharging my cell phone with a a USB cable because I dont' need an extra brick(transformer) to get the job done.

In fact, even though power over Ethernet is a great idea, I'll bet it's biggest competitor will continue to be good ol' USB. The only real advantage the Ethernet has is range and until it's commonly built into laptops and desktops It'll continue to be a very niche type of product.

TW

Re:What a shame...

[gcaseye6677]

Powering many common devices using USB, Ethernet, or other low voltage sources makes a lot of sense. Many devices that are in widespread use such as battery chargers, small lights, telephones, inkjet printers, do not need the full 120/240 volts to operate. Low voltage power could be a lot more convenient in many cases, since a standard electrical outlet and the transformer plug would not be required.

COOL!

[oGMo]

Now if I could have my PDA draw power from the wifi card, I wouldn't even need a battery!

Gigabit ethernet?

[mgs1000]

I guess it won't be compatible with gigabit over cat5e, since that uses all eight wires.

Re:Gigabit ethernet?

[YankeeInExile]

I sure hope your job isn't soothsayer.

There is no fundamental reason that DC power-pass could not be made to work with Gig-E, just as a single pair can simultaneously carry RF, DC power, and a tuning voltage (the feedline to the LNB for a DBS satellite).

Re:Gigabit ethernet?

[enigmals1]

Yes you can. The power is running on the same wires as the data. This is roughly the same technology as Broadband Over Power. The power is 60Hz but the data is MHz...or in your case, GHz. Little to no crosstalk.

Re:Gigabit ethernet?

[Trepalium]

So, of course the answer is, no, this is not compatible with gigabit ethernet. Gigabit signalling may be compatible with running power over those same lines, but the fact of the matter is the Power over Ethernet standard (802.3af) is incompatible with the gigabit ethernet standard (802.3ab).

Re:Gigabit ethernet?

[Anonymous Coward]

Actually 802.3af sends 48 volts DC over either the unused pairs (for 10/100baseT) or as a DC offset to the center tap of the ethernet transformers. This is how it would work with 1000baseT

BTW I work for a manufacturer of 802.3af compliant equipment.

Re:Gigabit ethernet?

[imroy]

No, still Mhz. IIRC, gigE is made of four 250Mhz channels. That's all four pairs of a cat5 cable, thus it's only half-duplex.

Re:Gigabit ethernet?

[Anonymous Coward]

I guess it won't be compatible with gigabit over cat5e, since that uses all eight wires.

A. You're an idiot.
B. You're an idiot.

A. Modern implementations of 1000Base-T work on 2-wire.
B. The Gigabit Ethernet phone is called the Cisco IP Phone 7971G-GE. As Cisco's highest-end phone, it's designed to allow unconstrained Gigabit Ethernet bandwidth from the network to desktops. The 7971 is powered by Cisco 10/100/1000 Ethernet switches that support the IEEE 802.3af standard for PoE.

Re:Gigabit ethernet?

[enigmals1]

Oh duh... that's right gig over copper does that.

Still, like I said... MHz. Way out of the range of 60Hz.

Stop the craziness!

[__aaitqo8496]

Power over Ethernet?
Internet over Powerlines?

What crazy things will they think of next? Power over powerlines and internet over ethernet?!?

Re:Stop the craziness!

[Anonymous Coward]

Sounds to me like somebody's trying to make a perpetual motion internet machine. If they do it with a computer, they might get a patent this time.

Re:Stop the craziness!

[Anonymous Coward]

yea, kids these days, they have it all!

When I was your age, we didn't have power over ethernet, we banged flint rocks together to make fire, and send smoke signals, and we were glad!!

Re:Stop the craziness!

[Anonymous Coward]

yeah? when i was young, our internet packets had to travel up hill both ways!

Re:Stop the craziness!

[Cyryathorn]

> What crazy things will they think of next?

Power over Wireless Ethernet

POW!

Re:Stop the craziness!

[Anonymous Coward]

Oh yeah, but when I was your age.. Oh wait, I'm actually so damn old that I've never even been your age!

Anyway, we didn't have, we didn't have .., oh damn I forgot what we didn't have, it must be this dementia thing.. (or maybe the bar-night, can't keep track of these things. comes with age) but yeah, we didn't have even the lack of anything, I'm telling you! Can you believe it? And were we glad? HAHAHA. Hell no. We complained about everything and everything. Especially about kids of these days.. and your days. Spoiled brats.

Re:Stop the craziness!

[swordboy]

Power over Ethernet

Ethernet over Power

Re:Stop the craziness!

[Anonymous Coward]

I was hoping for Cat's over ethernet, and um dogs over power lines..

Re:Stop the craziness!

[Anonymous Coward]

[Insert EtherKiller joke here...]

Re:Stop the craziness!

[CptNerd]

I was hoping for Cat's over ethernet, and um dogs over power lines..

Well, Ethernet already has Cat5, Cat5e, and Cat6, how many more Cats do you want (he asked, doggedly)?

What Stops Someone from frying a network card?

[Anonymous Coward]

Could a sloppy wiring job cause a fried ethernet card?

What about a device that provides a loop from the live pair to the data pair?

ac

Re:What Stops Someone from frying a network card?

[farnz]

Ethernet is an AC signal, power over Ethernet is DC. The AC signal is supposed to go via a transformer into the ICs, which should suppress the DC component entirely, so connecting power to data is harmless. Plus at these power levels, the card should cope anyway.

Re:What Stops Someone from frying a network card?

[bickerdyke]

the switch doesnt turn the power on until it confirmed that the device can handle it. It's a special combination of resistors between the wires that the switch tests for and then turns on the juice.

the next USB

[wattersa]

I for one would like to have my ethernet hubs use the standard wiring for power rather than a brick and AC adapter that I have to find an outlet for. Since telephones already do this it's just the next step in the direction of USB everything. Which seems to be a good thing (tm). Now I know how to set up a LAN in an unwired munitions bunker...

Re:the next USB

[Anonymous Coward]

stop buying low grade crap switches.

all my cisco gear uses standard power cables.

and if you are using a hub, what a loooooooser.

Re:the next USB

[Anynomous Coward]

I'm still angry at USB and FireWire for coming out with Yet Another Standard when Ethernet was already available, cheap and ubiquitous.

Think how great it would be to just plug in all the equipment into ethernet. Keyboards, mice, webcams, the lot. Just pair the devices with a button just like it is done with wireless mice.

But no, they really had to reinvent the wheel...

Re:the next USB

[ScrewMaster]

Yeah. Not only did they re-invent the damn wheel, but they did it very poorly, USB is still pretty flaky but Microsoft has the lead in vendor driver support. Besides, if you're a Microsoft you certainly don't want to standardize on a communications technology that your competition has integrated into its kernel and has been supporting for decades. No, you want something completely incompatible with everything else so that people that buy their USB cameras and USB scanners and USB this and USB that will be more inclined to buy Windows since it will "just work" rather than some competing OS that doesn't support it as well.

Re:the next USB

[IvyKing]

Now I know how to set up a LAN in an unwired munitions bunker...

As long as you are not planning to store munitions in the bunker....

While a lot of attention has been paid to safety in PoE, I'd want to make damn sure the implementation was sane before using it in a bunker. FWIW, I've actually worked in a couple of similar facilities.

the evolution of power over ethernet

[mmkkbb]

an early US attempt to self-power 10base-2 devices

The Germans are the first to adapt this technology to CAT-5

The US catches up

Re:the evolution of power over ethernet

[Anonymous Coward]

Dude, you spent way too much time on Google Image Search for that joke.

Razors!!!

[Clete2]

I want my networked razor and networked shaving cream!

The big question...

[FortKnox]

...is, of course, does that mean I can install linux on my razor?!?!?

Re:The big question...

[Anonymous Coward]

Cut your self shaving?

Yea... got root.

Re:The big question...

[ajax142]

No, but NetBSD seems to install fine!

Re:The big question...

[mi]

does that mean I can install linux on my razor?!

You, probably, will soon be able to, but the project will never get beyond single-user booting.

Oh, and you'll need proprietory firmware for the blades.

Re:The big question...

[chris_eineke]

That would be a bleeding-edge installation. ;-)

13W could be dangerous...

[Sheetrock]

Depending on the voltage and amount of power involved.

There are a couple of drawbacks to this plan: first, the increased caution that will be necessary in working with network cable (everybody's used to them being safe as phone lines) and second the possibility of burning out devices that weren't built with this standard in mind. Who's to say that a cheapie network extender installed in a rat's nest of cabling five years ago wouldn't start a fire when you hook something like this up?

Re:13W could be dangerous...

[MORTAR_COMBAT!]

an excellent post. volts don't kill people, amperes do! and since watts are the product of voltage and amperage, and voltage will be likely low... this would lead me to believe that yes, these could be dangerous devices with a good amount of current going through... a physics professor of mine once said "it only takes a single amp to stop your heart"... oh yeah! now we can play flatliners without the need for a power outlet! sweet!

Re:13W could be dangerous...

[Frennzy]

UL considers the average human (for testing safety purposes) to be about 500 Ohms. Since most PoE is around 12v, you end up with about 24 milliamps across a 500 ohm load.

For that to have a severely negative effect, it would need to cross your heart. Most of the current will likely go around your skin (you are your own faraday cage) so you most likely would never even feel it.

Plus, you would have to actually come in contact with it...which is pretty easy to avoid.

Re:13W could be dangerous...

[YankeeInExile]

Who's to say that a cheapie network extender installed in a rat's nest of cabling five years ago wouldn't start a fire when you hook something like this up?

How about the same UL (and their international equivalents) standards that already keep these same devices from catching fire if accidentally connected to telecoms lines.

Your assertion that ...used to them being safe as phone lines... begs the question*. Phone lines are not intrinsically safe, and the central office can easily provide several watts of power at 90VAC for ringers.

*Look, ma! Someone on slashdot who knows what 'begs the question' means!

In the US, at least, to meet Part 68, telephone gear must also handle line-crosses to 600Vac without creating a hazardous situation.

Re:13W could be dangerous...

[dourk]

You may assume telephones are safe, but the have a ring votage over 40v. Wiring up a the last jack in my house, stripped one of the wires with my teeth just as my buddy called.

It fucking hurt.

Re:13W could be dangerous...

[imsabbel]

Too bad you need a lot of volts to drive a lot of ampts through someones body, so you cant seperate them like that.
(just checked with my multimeter: my slightly sweaty hands have >5kohm from left hand to right hand even if i hold the contacts really tight. So 5V would give a milliamp, no matter if the source could deliver 50A...

Re:13W could be dangerous...

[willpall]

Actually, there's a constant DC voltage of ~48v (less by the time it gets to your house). The ring voltage is AC and closer to 100. Yes, it does fucking hurt.

Re:13W could be dangerous...

[shoppa]

Dude, that's almost as funny as the guy who built a glass case around a 10K ohm resistor with a sign that reads "DANGER! 10000 ohms!"

Re:13W could be dangerous...

[Anonymous Coward]

Depending on the voltage and amount of power involved.

You can be assured that the amount of power involved is no more than 13 W. Watts measure power. Joules measure energy. Volts measure electric potential (or potential difference). Amps measure current.

Re:13W could be dangerous...

[DJStealth]

(everybody's used to them being safe as phone lines)

Actually, phone lines can give you quite a shock if you touch them while a phone is ringing. (I'm not sure on current, but) the ring signal is given by a total potential difference of 96V across the 2 wires (+48 and -48). I believe regular usage signal is 24V; but I'm not sure on this, because I did an experiment and turned a phone into a portable tone generator by connecting a 9V battery to where the RJ11 plugs in.

Re:13W could be dangerous...

[PurpleFloyd]

Remember, while it's the amps that do kill you, you need enough voltage to push the amps across the heart. After all, you can easily hold onto the terminals of a car battery (12 volts, can deliver several hundred amps easily) with no ill effects.

It's all about Ohm's law: I=E/R (current equals voltage over resistance). Thus, to get 1 amp through a human body with a resistance of just 1000 ohms (which is a very low figure; the human body usually has more resistance fingertip to fingertip), you would need 1000 volts.

Even 110/220 volt house wiring isn't too dangerous when it comes to direct electrocution (although safety is always a good idea). The real reason you need wiring that's up to code is generally not electrocution as much as it is fire risks - short circuts can get hot. However, the current PoE specs are low voltage, low current - something that shouldn't cause any trouble if amateur wiring goes wrong, assuming that there is overcurrent protection in whatever provides power to the network.

Re:13W could be dangerous...

[Chazmati]

Is the UL definition for DC current? Or is that 500 ohms impedance, at the 60 Hz US standard line frequency? I wouldn't think 12V DC will hurt anyone (unless it's applied to your tongue, like testing 9V batteries; or if you drop a wrench across your car battery terminals, that might be bad...)

I had an e-mag lecturer who asserted that 60 Hz was selected as a national standard in part because this frequency worked well for the electric chair. I find this hard to believe, more likely he was trying to be a scary professor. But he did have a table of current (mA) versus harmful effects on the body. The class assumed that the higher the current, the worse the effect. "Death" was listed in the mid-range, though, followed by serious burns or something. Someone asked what was up with this and he thought perhaps the skin charred at high currects and acted as an insulator, preventing further fatal transmission of current.

Scary prof...

Re:13W could be dangerous...

[wwahammy]

Why in the world were you stripping wires with your teeth in the first place?

Re:13W could be dangerous...

[MarkGriz]

For that to have a severely negative effect, it would need to cross your heart

Don't forget "and hope to die"

Re:13W could be dangerous...

[SpooForBrains]

Used to live in India, where they take a cavalier attitude to wiring of any kind, so everyone gets their fair share of shocks, but none as funny as the time I rang my friend one afternoon, and got an engaged tone. So, I thought nothing of it and rode round there. When I got there he confronted me at the door ...

"Did you phone me a few minutes ago?"
"... yeah, why?"
"I was rewiring my phone! You just gave me a massive shock!" ... haven't been able to stop laughing at that mental image for years since ... I especially loved that I got an engaged tone!

Re:13W could be dangerous...

[Jeff DeMaagd]

Since most PoE is around 12v,

I am not sure what you are using, but the Linksys POE injector puts 48 volts in, just like the standard says. The Linksys POE splitter converts to 12V but that's only to be compatible with equipment that doesnt have a POE port.

I have another brand injector that also puts in 48 volts.

Re:13W could be dangerous...

[Myself]

Umm no, the voltage is still 48 when it reaches your house, if the line is open-circuit. When you take a phone off-hook, its resistance combined with the resistance of the line causes the voltage measured across the phone to drop. The resistance placed across the line is everything.

Re:13W could be dangerous...

[ccbutler]

well the power flowing through these Cat5e cables is low amprage DC current.

DC sources start to get dangerous at the Microwave Oven and TV levels.

Even if you put a kink in this stuff it wouldn't cause a safety risk.

Re:13W could be dangerous...

[Eraser_]

Same reason I was holding a telephone wire pair with my teeth a few years back. No tool at hand to do the job properly. Luckily the phone didn't ring, so all I got when I accidentially touched my toungue to the pair was a gently "buzz" feeling which actually took me a minute to figure out.

Re:13W could be dangerous...

[Frennzy]

It's for DC resistance, not AC impedance. ( I used to build energizers for electric fences, and the owner of the company wanted to get UL marked. Unfortunately, the total energy transfer in our design was two orders of magnitude higher than UL would allow for...any less any the fences were ineffective, so we never got UL marked). We used a variety of DC voltage levels, up to about 10k (for Buffalo) with a 17ms pulse. Let me tell you, I got hit more than once..and that stuff *hurt*, but it never killed me.

Again, a lot of the current goes around your body, not through it. Though there is the story about the military instructor who was explaining exactly this concept to his class, and poked the sharp ends of two leads (connected to a 9v battery) into each of his thumbs, and it supposedly killed him. Check snopes, I'm too lazy to verify it.

Re:13W could be dangerous...

[Frennzy]

You're absolutely correct, I don't know what I was thinking. 48 volts can be felt for sure, but most of the current still travels across your skin, not through your body.

Re:13W could be dangerous...

[krbvroc1]

How about the same UL (and their international equivalents) standards that already keep these same devices from catching fire if accidentally connected to telecoms lines.

You are only looking at half the picture. Its not just the UL listing of the device, but its the installation. While the UL listing helps, building codes (at least in the US) also require that a fully licensed electrician install electrical lines. The local building authority also requires multiple inspections (planning, rough-in, final), as well as collecting tax on the whole process. Do we want installation of Ethernet cabling to require licensed, regulated, and taxed checks and balances? It would seem to me that Power over Ethernet might head us in that direction, especially if the wattage is increased (and perhaps after a fire or electrocution because someone attempts to plug their ethernet cable into their modem jack or their USB port).

Re:13W could be dangerous...

[jpmkm]

The distance from the earth to the sun is over 40 million miles.

Re:13W could be dangerous...

[lyonsden]

I got hit more than once..and that stuff *hurt*, but it never killed me

Are you sure?

Re:13W could be dangerous...

[owlstead]

That's why the devices first _check_ if the other device is a power over ethernet device. I've read the RFC of the standard, and this functionality is already included.

Re:13W could be dangerous...

[Anonymous Coward]

Let me tell you, I got hit more than once..and that stuff *hurt*, but it never killed me.

I'm sorry you have to endure with the impaired thinking...

Re:13W could be dangerous...

[Tassach]

you can easily hold onto the terminals of a car battery (12 volts, can deliver several hundred amps easily) with no ill effects.

I challenge you to videotape yourself demonstrating your theory. You can have your next-of-kin digitize and post the tape if need be.

Re:13W could be dangerous...

[kmahan]

The spec addresses issues like "devices that can't handle it." You just have to RTFS.

That 13W isn't always there. The device has to be POE enabled. The hub supplying power senses the device. It then measures a resistance across one of the pairs looking for a very specific resistance. That's what specifies IF PoE is wanted, and then there are different current limits you can request. The hub end is required to limit the current supplied and also monitor for faults (and if so disable the power).

The spec isn't just some yoyo hooking up an ac adapter to a supposedly unused pair and saying "it works.."

Re:13W could be dangerous...

[2centplain]

Analog telehone ring signal is about 100 volts, 20 hz. Yeah, it hurts, but only intermittently, depending on the ringing pattern. (Remember when phones actually had real metal bells and magnetic coils that require this sort of signal to make a noise?)

Re:13W could be dangerous...

[Lumpy]

first, the increased caution that will be necessary in working with network cable (everybody's used to them being safe as phone lines)

oh I love people like you :-)

safe as phone lines? please stick a phone cable in your mouth and then dial that phone number from your cellphone.

you will see how "safe" they are when you get the 90volt AC ring signal on your toungue.

there is a battery voltage on a phone wire also capable of running equipment. many phones draw power from the phone line to power the speakerphone amplifier and indicator led's.

Re:13W could be dangerous...

[Mr. Competence]

Actually, it only has to be a licensed electrician (generally) if you are hiring someone to do it. If you do it yourself (or have someone help you for free) it doesn't matter.

Re:13W could be dangerous...

[KingOfTheNerds]

One time I licked a phone line to see if it was in fact plugged into the wall behind my desk. It would have been a hard crawl to get back there to check- and I assumed that phone line voltage was pretty low (like licking a 9V). Oh man did a get a good shock from that. Moral of the story: Power over Ethernet is a good thing, just don't lick it and you'll be fine.

Re:13W could be dangerous...

[step0130]

Without a load attached to the cable (i.e. you grasping a live wire), there is no power. Even if you were holding on to a wire and were grounded, the total power delivered to the load (you) depends on the voltage and the resistance (P=V^2/R). Assuming ~12VDC for most PoE, and typically 500 ohms resistance, you are only looking at 24mA of current and 288mW, and unless that goes directly across your heart (by completing the circuit with your other arm) at best you will feel a little tingle. The biggest danger comes during lightning storms where huge voltage transients can be induced on these lines due to the large electric fields genereated during a lightning strike. That is why your grandmother always told you never to talk on the phone during a storm.

Re:13W could be dangerous...

[amembleton]

Similar thing happened to me a few years ago at my parents house. I was stripping a telephone wire with my teeth, and ended up blowing a fuse in the box up the road. Had to wait a few days for BT to fix it.

Re:13W could be dangerous...

[T-Ranger]

Now that you mention it...

In Nova Scotia, any commercial work, and any other work of more then 4 drops, requires a building permit, and a licensed installer. When this came out, oh 4 years ago, licensed installer == licensed electrician. They have progressively been moving towards a data/voice trade designation, distinct from being an electrician, but this has yet to turn into, say, a (multi-)year course at the community collages.

The issue of licensing (or rather, properly done jobs) isn't so much with electricity, but with plenum/non-plenum, punching holes through firewalls, etc. I don't know the local regs, but the TIA structured cabling specs do have some very specific grounding requirements...

Re:13W could be dangerous...

[Anonymous Coward]

A moronic post. Yes, Amperes are what kills. But Amperes in a resitanceless wire is NOT THE SAME as what the current will be across a human body (or any other resistor).

If this wiring is running at 5V, then it doesn't matter A DAMN BIT how much current is potentially running through it with no resistance. What matters is how much current flows ACROSS A LOAD when connected across the leads. And THAT is a function of 1.) The voltage, and 2.) The resistance of a load.

Sorry, but this is like arguing a 1.5V battery is dangerous--if you short it out with a length of copper wire, you could have 10's or 100's of amps running through it! Well, yeah, but it's still just 1.5V. The amps don't just "keep flowing" unless you've got some kind of very powerful inductor in the circuit (no, not a loop or two of cable on the floor--something with a LOT of windings).

Bottom line: The amount of current flowing through a circuit in no way makes it dangerous. It's the voltage that does that.

This is like arguing that sticking a pair of forks into the prongs of an outlet is NOT dangerous, because there's NO amps flowing between the 2 sides of the outlet at the moment....

Re:13W could be dangerous...

[kesuki]

those are my favorite kinda phone to open up and mess around with... wheee

Re:13W could be dangerous...

[ReelOddeeo]

I did the strip the telephone wire with my teeth once too. :-) You're not the only one.

Re:13W could be dangerous...

[Anonymous Coward]

Damn you mean it isn't what yoshi had rigged up on TSS*? FEH! Ruin all the fun with 'standards' and saftey nonsense!

*= when there WAS A TSS

Re:13W could be dangerous...

[krbvroc1]

Actually, it only has to be a licensed electrician (generally) if you are hiring someone to do it. If you do it yourself (or have someone help you for free) it doesn't matter.

Not in this State/County. A permit is required before doing electrical work. Only a licensed electrician is able to pull a permit. There is a 'homeowner' clause, however it requires that you take (and pass) a detailed test which assesses your knowledge of the National Electrical Code 2002.

Mr. Competence, I think I know your brother, 'In'--I work with him.

Re:13W could be dangerous...

[b0s0z0ku]

you can easily hold onto the terminals of a car battery (12 volts, can deliver several hundred amps easily) with no ill effects.

I challenge you to videotape yourself demonstrating your theory. You can have your next-of-kin digitize and post the tape if need be.

I've stuck my (sweaty) hand across the terminals of a car battery by accident and I felt exactly ... nothing. No pain, no muscle twitching, nothing. 12 V simply doesn't push enough current to hurt you, unless maybe the battery leads are attached to needles stuck under your skin. Cars are 12V precisely because 12V is considered to be a safe voltage, although with the proliferation of electrical accessories in cars, several manufacturers are thinking of going to 36V systems.

-b.

Re:13W could be dangerous...

[b0s0z0ku]

One time I licked a phone line to see if it was in fact plugged into the wall behind my desk. It would have been a hard crawl to get back there to check- and I assumed that phone line voltage was pretty low (like licking a 9V). Oh man did a get a good shock from that.

'phone lines are 50VDC when the phone is on hook, about 12VDC when the phone is off hook, and 100VAC at about 20Hz when the phone is ringing. Ouch! When working on phone lines in your house, always take one extension off hook to avoid getting zapped.

-b.

Re:13W could be dangerous...

[sexecutioner]

Yeah, I did this, but I was stripping the plugged in phone line with my teeth*. The other lead touched my nose and I got one hell of a shock through the roof of my mouth. I looked it up, here in Oz the phones are nominally 50V.

*I was mid call to a friend and one of the dogs chewed through the lead. I planned to quickly strip them and twist the line back together before the call was dropped. Even with the shock I was quick enough, got the twisted the leads together and went on with my conversation.

Re:13W could be dangerous...

[JLMore]

I was present at one of the first trials of this technology, before the bugs were worked out.

We installed new cubicals and had them wired for both ethernet and electricity. The electrician made a mistake and wired the electricity to the ethernet terminals - 220 volts.

Fortunately it burned out the ethernet cards in the local and server computers before it did any more damage.

(That may be why the reduced it to 13V ;-)

Re:13W could be dangerous...

[Lord d'Eath]

No need. Dan already has. The photographic proof.

Re:13W could be dangerous...

[dourk]

Clench wire in teeth. Pull.

All my tools are built in.

Re:13W could be dangerous...

[Anonym1ty]

Too bad you need a lot of volts to drive a lot of ampts through someones body

Watts were Amps times Volts.... And you could have plenty of Amps at fractions of a Volt - and vice versa.

1 Amp at 30 Volts can Kill you, so can 30 Amps at 1 Volt. Watts are what count.

Re:13W could be dangerous...

[willpall]

That 48v immediately drops when the circuit is closed, end-of-line resistance or not. 4 miles of 24 guage wire presents significant resistance all by itself. PS The CO voltage, although refered to as 48v is really closer to 54v.

Re:13W could be dangerous...

[Myself]

To re-re-restate what should be elementary who's ever touched a resistor:

If you "close" the circuit with a high value resistor (say a few megohms), the voltage measured across the resistor will be essentially the same as the voltage measured where the pair leaves the office.

If you "close" the circuit by shorting the wires together, then by definition, the voltage measured across the junction will be 0 volts, with the rest of the loop burning off the current as heat.

Measuring open-circuit voltage with a high-Z solid state meter should show above 50. Measuring it with a moving-coil analog meter will vary depending on the coil's resistance (typically a few k). It's just a galvanometer after all, and depends on some nontrivial current flow to cause needle deflection.

As I stated before, it all depends on the resistance of what you place at the end of the loop. The average human touching the wires presents a resistance of 1k or higher. Most buried cable is 20 or 22ga, sometimes 19ga for longer distances. In any event, the telcos make every effort to keep total loop resistance under 1300 ohms, with the average being closer to 300.

Doing the math here, each side of a 300-ohm loop will be 150 ohms. Let's take 1200 ohms for the human, a number indicated as reasonable by what I've read, and one which makes the math easy. Total circuit resistance is now 1500 ohms. Call the voltage 50, and we end up with 40 volts across the human, and 5 volts lost on either side of the pair.

You're right on the 54 volts thing, the system is nominally 48 based on 2 volts per battery cell, but "floats" at 2.25 per cell to keep the chemistry happy. It drops to 48 very soon after commercial power fails. All the gear should be designed work right down to 42 or less, as lead-acids exhibit a downward slope during discharge.

Also, to clear up some ambiguity from another poster elsewhere in this thread: Ringing is stated at 90v, 20Hz, sine wave.

Re:13W could be dangerous...

[Anonymous Coward]

Its actually 52v when a phone rings rings and yes it will leave a mark. I have had my hand on a 66block when a phone is ringing so many times that I can almost tell you the rack in the CO it came from. I dunno , I kinda kinda like it now now.

Re:13W could be dangerous...

[ScrewMaster]

60 Hz. was selected as a national standard because Tesla worked out the numbers and George Westinghouse went along with him, and the rest of the country ended up going along with Westinghouse. Westinghouse was concerned about power transmission and 60 Hz. was selected for efficiency with the generator and transformer technology of the day. Remember Tesla's proficiency with those.

Your professor is a bit confused about the electric chair business: it was Thomas Edison who claimed publicly that Westinghouse's 60 Hz. system was much more dangerous than Edison's own direct current power system. This was strictly a marketing ploy: he and Westinghouse were going head-to-head in an all out corporate war and Edison wanted to win, badly. He had no scientific basis for his claims. In other words, he lied, publicly and repeatedly. He even went so far as to have a major correctional institution that was building a new electric chair facility install Westinghouse generators in order to "prove" how dangerous alternating current could be. The reality is that Edison was way off base: direct current is substantially more risky than alternating: for example, if you grip a pipe charged with 120 VAC, you will get a nice shock but will be able to release your hold. The jolt might cause your heart to fibrillate but most likely you'll survive. Grab that same pipe with 120 VDC and your muscles will lock and you won't be able to let go ... your heart will also stop dead if the current happens to pass through it. A lot of lives were spared over the years because we didn't go with Edison on that one. The other reason to rejoice is that a DC power distribution system would have required power plants plastered all over the place since transformer operation (and hence high-voltage landline transmission) would have been impossible. Today we could probably do it with high-powered DC-AC inverters, but that technology was way beyond Westinghouse and Edison.

The only thing that saves us from instant death the first time we walk across a carpeted room in dry weather is our epidermis. That layer of dead tissue makes an excellent electrical insulator. Otherwise, the first static spark you drew touching a doorknob would stop your heart. Remember, the insides of your body are an ionized, highly-conductive mess: a hundred-odd pounds of adulterated salt water. If you stuck a couple of pins in each index finger, and put those pins across a flashlight battery, you would probably die. Your bloodstream would conduct that tiny current flow directly through your heart. But touch those same terminals with the outer layers of your skin intact: no problem.

And I'm not making this up: if you've ever been in a hospital burn unit, you would see that everything in those rooms is heavily grounded, and extreme precautions are taken against static discharge or any other electrical artifact reaching the patient. It's amazing. I worked in a lab at a major teaching hospital / university for a while, and I noticed that there were these odd metal plates with heavy-duty green leads hanging out of them, sticking out of the walls and floors. I asked, and was told that the lab space was a converted burn unit. People that have had significant areas of their skin burned off are fatally susceptible to even minor electrical discharges.

Re:13W could be dangerous...

[upsidedown_duck]

Depending on the voltage and amount of power involved.

The amount of power involved is...13 watts.

BTW, those low-voltage lighting systems for driveways, etc., are pretty safe at 12 volts and not all that much wattage. As long as the potential is really low, just the resistence in our skin would be enough to protect us.

Re:13W could be dangerous...

[willpall]

Kind of what I was saying, but much more thourough. That 40v across the human is what I mean't by "40v once it reaches your house" Measuring an open circuit provides a somewhat meaningless result when that open circuit includes such a large amount of wire. It will tell you the correct source voltage, and if that's what you're after, then the measurement is sound. If you want to find out the available "usable" voltage, then yes, you have to take into account the resistance of all components you're playing with. Umm, so yeah. Sounds good to me.

Re:13W could be dangerous...

[Frennzy]

Wrong.

It's not that epidermis is an insulator, it's that it is a conductor. Sweat, salt, humidity: all of these things contribute to your skin being a faraday cage.

This brings to mind one of the greatest fallacies of the modern age: to wit, staying in your car during a lightning storm keeps you safe because you are 'insulated' by the tires.

BS. The only thing that keeps you safe in your car is the metal skin of that car. An average lightning bolt has enough potential voltage to conduct right through hundreds of feet of 'tire'.

Re:13W could be dangerous...

[scaryfish]

It's happened.

Re:13W could be dangerous...

[Wocko]

Yep, definitely over 40 million.

Re:13W could be dangerous...

[jonoton]

There's no power on the ethernet line unless there is a device at the other end requesting power.

So handling the ethernet cables is as safe as it's ever been...

Re:13W could be dangerous...

[lars_stefan_axelsson]

Your professor is a bit confused about the electric chair business: it was Thomas Edison who claimed publicly that Westinghouse's 60 Hz. system was much more dangerous than Edison's own direct current power system. This was strictly a marketing ploy: he and Westinghouse were going head-to-head in an all out corporate war and Edison wanted to win, badly. He had no scientific basis for his claims. In other words, he lied, publicly and repeatedly.

No that's not true. Edison had plenty of data from animal research. He even had a traveling road show that demonstrated (on sheep mostly) that they died when a comparatively much lover AC voltage was applied than when a DC voltage was applied. "You could turn the dial much higher." And it wasn't all sheep, they even electrocuted an elephant in New York (that had been condemed to death for killing its keeper). He even had billboards that said: "Don't use the executioners electricity in your homes!" (or words to that effect).

AC was indeed used for the first electrocution, suggested by Edison who build the apparatus. Westinghouse wisely refused to sell any equipment but then Edison arranged a purchase in secret and shipped it in unmarked crates to the place of execution. The first electrocution itself was a horrible botched affair, where many of the witnesses fainted from the stench of burning flesh. And the condemed man was first thought to be dead and the steam let out of the engine, only for the officials realising that he was still alive and everyone having to wait for the steam engine to be fire up again.

Also, your statement that DC is more dangerous than AC is not quite as straightforward as you make it to be. While at higher currents DC does tend to lock the skelettal muscular system more readily than AC; that doesn't in fact kill you as easily as electricity induced teatanus of the heart tends to resolve once the current is removed (hence defibrilation units use of DC), i.e. the heart starts again. AC otoh tends to cause fibrilation of the heart, which won't resolve itself and kill the patient (unless defibliration is available). We're speaking here of 50/60 Hz AC of course, as AC in the ten-kilohertz range or so is practically safe due to skin effects (your skin is a pretty decent conductor as other's have pointed out). Also, AC will also induce tetanus, though I'm not sure about 120V in the common case (Europe being on a 400/230V system. 230V can be enough to 'stick you on the circuit'.)

The best links I could find was this and this. Note the table half way down on the second page that lists the amperage needed for various effects on the body. I've had a better link before, but I can't find it now.

Re:13W could be dangerous...

[MORTAR_COMBAT!]

and your post disagrees with the moronic links I provided... how?

Re:13W could be dangerous...

[jbridge21]

No no, that was one of the big pendulums that show the rotation of the planet over a 24 hour period. They are really tricky to get going right, and they were having lots of problems with random people walking by touching it and messing it up. So they put up that sign around the edge and the number of incidents went way down :)

Re:13W could be dangerous...

[ScrewMaster]

Like I said, he had no scientific data to back up his claims. Edison's "research" was as faulty as anything else he said about A.C. ... Edison wanted to own that monopoly and proved that he would do anything to do it. He played very, very dirty pool with his competitors in the best of times (in his own way, a prototypical Bill Gates), and when Westinghouse began to take over the market (remember, Edison had no long-distance power transmission capability) Edison responded with trick after dirty trick. It probably didn't help matters one bit that it was his own ex-employee, Nikola Tesla, that was fundamentally responsible for Westinghouse's technology.

Electrocuting some animals and saying "I could have turned the knob higher" might constitute proof to the lay person (which was what Edison was trying to do so that the public would do his dirty work for him) but is irrelevant in any other context. Thomas Edison was a respectable inventor (if one who was strictly empirical and completely unscientific) but his business ethics were reprehensible. His secret installation of a used Westinghouse generator set for use in the Kemmler execution was diabolical (also, I suggest you read up on one Harold Brown, inventor of the electric chair ... his collusion with Edison was legendary.) Most of the "animal experiments" you refer to were performed by this Harold Brown, and were equally suspect. In one, a dog survived 800 VAC but died at 1000 VDC ... there are many factors that could account for that difference (other than the intrisinic "safety" of one type of current over another) but the fact that Brown performed this "scientific experiment" means the results are scientifically meaningless, although they had considerable marketing potential. Also, as the experiments were done using voltages several times the line voltage in use at the time, they had even less actual relevance. But after his death, Kemmler was described as having been "Westinghoused" so I guess Brown's work served its purpose. Edison himself, upon cross examination, displayed a remarkable ignorance of the effects of electricity upon the human body in spite of all his public rhetoric. In any event, that was one battle that Edison lost, fortunately for us.

My statement about DC being more dangerous than alternating current referred to line voltages (that, after all, is the topic of discussion) and there it most definitely is, and for the reasons I described. Alternating current won't lock your muscles: they'll simply vibrate, but DC will and if you happen to be gripping that electrified object, you will find you can't let go. Bad news.

Re:13W could be dangerous...

[lars_stefan_axelsson]

Most of the "animal experiments" you refer to were performed by this Harold Brown, and were equally suspect.

Not all though. There was a series of experiments with sheep that demonstrated that AC did indeed kill at much lower voltages. And as that also happens to be true it's not an unreasonable claim. That Edison was foremost a marketing genious/entrepreneaur and a mediocre inventor at best is not up for dispute IMHO. (Oh, and BTW Edison suggested that the process be called Westinghousing, it didn't stick. It was 'electrocution' from the get go. The medical profession didn't use that word for obvious reaons though.

My statement about DC being more dangerous than alternating current referred to line voltages (that, after all, is the topic of discussion) and there it most definitely is, and for the reasons I described. Alternating current won't lock your muscles: they'll simply vibrate, but DC will and if you happen to be gripping that electrified object, you will find you can't let go. Bad news.

No, that's not true. AC will also "lock" your muscles (i.e. induce tetanus) happened to my father once in his youth (when he was training as an electrician). And at quite low currents. The link I gave you listed the following values: "Painful, unable to let go of wires" (held in hand that is). Men/Women 76/51 mA DC, 16/10.5 mA AC (60Hz) and 75/50 mA AC (10kHz). One source gives 20mA for men AC (60Hz). These are experimentally obtained figures (Berkley). Fibrilation is the same story though at higher currents (and this data is much more uncertain as it's based on animal research. Some sources claim human heart fibrilation possiblity as low as 17 mA AC 60Hz).

Now the reason I said that the US line voltage sitation is problematic is that the current depends on the resistance (which also depends on the geometry of the situation). If you wear your wellingtons and keep your left hand in your back pocket (and always first touch any wire with the outside of your fingers) then killing yourself with a line voltage source (even in Europe) will be very difficult. Conversely, sweaty hands gripping a bare wire wearing a gold ring standing with your bare feet in salt water is another scenario altogether. (As an aside that was Edisons suggestion for the method of electocution: Have the hands of the condemned in two baths of saline solution. That (probably wisely) wasn't chosen.) That said, DC is still safer than AC in the 50/60 Hz range (it's an unfortunate frequency choice as it affects nerves more than other frequencies would) at any voltage. The reason we use AC is purely for practical purposes, not safety related. And as we're discussing safety we should of course mention that the most common injury associated with electricity is being shocked and falling from a ladder. It's not for nothing that the old school electricians use wooden ladders. AC or DC doesn't factor in to that scenario.

There's more on the net about the biological effects of electricty than you can shake a stick at such as the frequency dependant resistance of various body tissues etc. etc. etc. ad nauseaum.

Re:13W could be dangerous...

[rthille]

Even sweaty, your resistance thru your body is still quite high. 12v combined with that high resistance (my DMM says my tongue is 500K ohms, one probe in each hand was 1.5M ohms) doesn't push enough current to hurt you.

Re:13W could be dangerous...

[lars_stefan_axelsson]

That Edison was foremost a marketing genious/entrepreneaur and a mediocre inventor at best is not up for dispute IMHO.

Following up to my own post as I can't edit the previous one.

In hindsight, "second rate" is a bit stronger than I intended. I'd instead like to say somethings along the lines of: Edison was a genious level entrepreneaur first and an inventor second.

Already done before...

[xortw]

etherkiller

Re:Already done before...

[Anonymous Coward]

goatse, get your goatse here...

Short circuit

[totallygeek]

I went to a company that cabled about 100 drops. When certain network items did not work properly, they tried everything to figure out what the problem was. Finally, one device was plugged in and did not work at all. It turns out that the cabling was wired with "just the same colors on one end as the other". The installers actually created an elaborate mapping on paper saying, wire 1: red, red/white, blue, blue/white, brown, brown/white, green/white, green. They would look up each cable on this run sheet before punching down the other end. The device that did not work evidently was not "looked up" correctly, and so there were no valid pairings. If this had been POE, something would have been fried.

Another company I worked with found out that their cable guys simply wired everything with 2 pairs only. They would punch down 1,2,3,6 and then cut the remaining wires completely. POE wouldn't work there either.

It is amazing how some companies attempt to save money by getting monkeys to install cables.

Re:Short circuit

[HaeMaker]

Actually, the company who only wired two pair can get PoE for switches that provide PoE, but not external injectors. There are two standards for power, if the power is injected off the switch it uses dedicated pairs, if it is injected on the switch it uses the data pairs (phantom power).

Re:Short circuit

[Gadgetfreak]

Just because someone doesn't do their job correctly doesn't mean it's a bad idea for info lines to carry power. Considering that all the wires in Cat5 equipment aren't always used, I don't see why a standard can't be developed. The basic phone line carries power all the time, and a ringing voltage spike.
I just got finished with the home inspector for my new place. We found 4 outlets wired with the hot/neutral reversed. They're outlets. Nothing new and confusing to anyone currently alive.

Anyone can make a mistake, but people need to learn to test things before they use them.

Re:Short circuit

[YankeeInExile]

And it is a trivial case to inject power into the ethernet stream ... look at a circuit for putting repeater power on a T1 span from the late 70s ... You just need to redo the magnetics to handle the higher passband of Ethernet.

Re:Short circuit

[DustMagnet]

If this had been POE, something would have been fried.

The power isn't provided until after the port is probed. The probing specs look pretty mild. I find it hard to believe anyone was stupid enough to let PoE damage any standard ethernet ports when miss wired.

Re:Short circuit

[Anonymous Coward]

I live in an apartment building built in 1909 with both knob-and-tube wiring providing power to baseboard outlets and conduit exposed on the walls providing power to outlet boxes tacked on the outside of the walls. Of the twelve outlets in the six rooms, three have recepticles for ground pins, and of those three one is in a closet. Only two of those test as grounded, and one of those has hot and neutral reversed.

I love taking a shower in the bathroom under the knob-and-tube wiring that runs directly over the bathtub, above the dropped t-bar ceiling that would hold acoustic tiling if the bathtub in the apartment above didn't occasionally leak through into my bathroom right at the joists where the knob-and-tube wiring passes through (unlike modern electrical code, knob-and-tube runs perpendicular to joists).

Heh. One way to check if a cable is still in use.

[Anonymous Coward]

Or vice versa, a way to make your cable monkeys more careful about what cables they cut.

but..

[Anonymous Coward]

will it power my computer?

Re:but..

[Drishmung]

Not unless your computer only requires 13w.

Which is a very interesting thought. Power has been essentially considered 'free', except for laptops. The concern has been much more with cooling. PoE though could provide a huge impetus for low power PCs. Eventually.

That ARM chip starts to look really interesting...

wifi?

[Anonymous Coward]

What about a small PoE wifi AP? It could be short-range and low-power, just so that you could plug it into a nearby ethernet jack rather than running CAT5 to your laptop. Convienent.

DC power -- sad failure of standartization

[mi]

As much as the AC standard can be considered a success -- even if different regions use different voltage and connectors, the sorry state of the DC power is an outrage.

Why does every DC-using device come with its own adapter, and uses its own voltage? Why could not we standardize that?

Maybe, this "power over Ethernet" initiatives (together with the "power over USB") will spell the end of power-strips with curiously shaped "bricks" constantly falling out of them...

Re:DC power -- sad failure of standartization

[GlassUser]

It's happening. Slowly. Somewhat. Even over the past few years, I've noticed things slowly gravitating to either 5v or 12v. I think part of this has to do with the 12v lines used by hard drives (eg the mini-itx market is pushing htis), and the 5v is used by a lot of chipsets, apparently (since every decent PDA seems to run off 5v). So we might get there eventually.

Personally I think it would be great if 12vdc was the "standard" dc power supply, and you can easily get or make an adapter to turn it into 5v.

Re:DC power -- sad failure of standartization

[D0 J00 W4n7 K4r473]

I, for one, welcome our new power over ethernet overlords. I have such a tangle of power cords for everything in my office that one less cord for a few devices would be a welcome change.

Re:DC power -- sad failure of standartization

[wfberg]

Cell phones usually run on 4.8V, because you can only get multiples of 1.2V when you couple rechargeable batteries in series (non-rechargeables carry up to 1.5V, so that's why 3/6V is common in toys and the like).

In fact, 1.5V (or a multiple thereof) was a pretty good standard until rechargeables came along. That's also why one of them flatty squarry batteries is 9V, a multiple of 1.5..

The problem of course is that while you can easily go from 1.5V to 3V and up by coupling batteries in series, if you've got an adapter hooked up to the mains, it usually only outputs one voltage, or it would have to have a switch on it. Those things are hideously expensive for some reason, $30 for a simple adapter with not to much power.

It would be trivial to design a connector that has a socket with pins either present or missing just for the purpose of indicating which AC voltage it wants. You'd need quite some pins to cover the bases though - multiple of 1.2 or 1.5, 1,2,4 or 8x base voltage, expected number of amps, one pin per bit of information makes for brittle connectors..

Re:DC power -- sad failure of standartization

[NardofDoom]

Most solar systems run 12V DC, and I noticed all of my networking equipment does this, too. Maybe there's a market for solar powered repeaters?

Or maybe I could put one in my shed so I can hide there when my mother-in-law comes over.

Re:DC power -- sad failure of standartization

[theLOUDroom]

Why does every DC-using device come with its own adapter, and uses its own voltage? Why could not we standardize that?

Because if you did, you'd still need a bunch of DC-DC converter bricks.

An external hard disk has different power needs than a 5.1 speaker system which has different power needs than a cordless drill (charger), which also has different power needs than my cellphone. If you demanded that all that stuff have a plug on it for a certain DC voltage, all you're going to see is whole bunch of external DC-DC converter bricks.
Sure some manufacturers will build them into the box itself (just like all those products that DON'T need AC/DC bricks now) but many are going to use an external brick for all the same reasons they're already doing so.

What you're asking is like asking "Why do we have all these different types of screws, can't they just pick one size?"

Re:DC power -- sad failure of standartization

[Garak]

Most electronics have a DC-DC converter built in these days. MY little linksys wireless router for example runs off a 12vDC wall wort but internally everything is running at 3.3v

Switching regulators are pretty damn effiecent, some text even refer to them as DC transformers. They are also pretty small, ususally just a small 4 or 5 pin device with a few small inductors, resistors and capacitors.

Re:DC power -- sad failure of standartization

[legirons]

"Maybe this will spell the end of power-strips with curiously shaped "bricks" constantly falling out of them..."

As to the "falling out" bit, one good solution is British Standard 1363 - I never did understand why people put-up with power cables that get disconnected every time you move them too far.

Re:DC power -- sad failure of standartization

[mi]

Because if you did, you'd still need a bunch of DC-DC converter bricks.

I'd need a lot less of them, than I have now. There being a standard of, say, 12V or 24V would give the designers and manufacturers a good incentive to stick to it, unless their specific product requires something different.

What we have now is gratuitous diversity of the "bricks", which should be interchangible, but are not. Not all manufacturers even have the decency to standardize within their own products.

What you're asking is like asking "Why do we have all these different types of screws, can't they just pick one size?"

Similar -- in that I'd like to see less (not one) variety of screws out there, thus requiring fewer different screwdrivers.

Re:DC power -- sad failure of standartization

[RTMFD]

"Bricks?" I prefer to call them "wall-warts". :^)

Re:DC power -- sad failure of standartization

[thenightisdark]

Actually, its more like Philips Screw drivers, and Flathead. For many screws, 2 types of screwdrivers will allow you do use all sizes of screws.

Re:DC power -- sad failure of standartization

[theLOUDroom]

Most electronics have a DC-DC converter built in these days. MY little linksys wireless router for example runs off a 12vDC wall wort but internally everything is running at 3.3v

You're kinda missing the point though.
Sure, it's possible, but that doesn't mean it's worth doing.

You're talking about going from AC to power to some sort of "standard" DC and then finally coverting to power the device actually uses. What you end up doing as adding ANOTHER brick to your desk to provide this "standard" DC power (while still needing a bunch of other bricks). Basiaclly, you've bought yourself nothing.
All these devices are still going to need a similar number of components as they were using previously to filter their new shared power supply and convert it to the proper voltage. The O.P. suggested that there was no standardization of DC power supplies but that's not reaslly true. Most supplies use a fairly standard voltage like 5V, 9V or 12V, and a standardized connector consistent with that voltage. If you loose the power supply for something, chances are you can buy an new supply online with the proper connector and voltage fairly easily. Heck, Radioshack stocks a whole bunch of that stuff.

Switching regulators are pretty damn effiecent, some text even refer to them as DC transformers.

Sure they're efficient, but two of then in series is less efficient than just using one of them. It costs more, is bigger and fails more often too.

They are also pretty small, ususally just a small 4 or 5 pin device with a few small inductors, resistors and capacitors.

If you ignore all the other stuff you need to make an actually decent power supply like input/output protection, filtering and storage capacitance.

Besides different devices needing different voltages and current capabilities, they also have other requrements. Like ripple current. Or transient response.

Re:DC power -- sad failure of standartization

[multipartmixed]

> Most solar systems run 12V DC

Funny, I thought our solar system was powered by gravity.

Re:DC power -- sad failure of standartization

[theLOUDroom]

As to the "falling out" bit, one good solution is British Standard 1363 - I never did understand why people put-up with power cables that get disconnected every time you move them too far.

Because it's safer than ripping the outlet out of the wall or the wires out of the connector.

That's really the alternative. At some point something's gotta give. If not the connector, it's going to be the wall plate of the cable, either or which could lead to a fire. By compasion, the plug falling out of the socket is pretty safe.

Re:DC power -- sad failure of standartization

[theLOUDroom]

I'd need a lot less of them, than I have now. There being a standard of, say, 12V or 24V would give the designers and manufacturers a good incentive to stick to it, unless their specific product requires something different.

Nearly everything is still going to need a power contitioning stage, even if it does run on the same voltage. You don't want your electric razor screwing up writes to your external hard disk. Those wall warts (and their more manageable cousin the "line lump") help provide isolation between the diffent devices on your power lines.

What we have now is gratuitous diversity of the "bricks", which should be interchangible, but are not. Not all manufacturers even have the decency to standardize within their own products.

I would say that manufactuers do mostly restrain themselves to fairly standard supply voltages like 5V,9V,12V etc. The thing to remember is that most of these companies aren't making the wall bricks that come with their products. They're considered a fairly standard widget, and they have even somewhat standardized the connectors they use. Chances are you can that that Linksys wall wart into Radioshack and they'll be able to give you a functional replacement.

Re:DC power -- sad failure of standartization

[mi]

You are just arguing for the sake of arguing, aren't you?..

Nearly everything is still going to need a power contitioning stage, even if it does run on the same voltage. You don't want your electric razor screwing up writes to your external hard disk.

Somehow, my vacuum cleaner does not screw up my washer nor drier. My lady's hair-drier does not affect our microwave, and our DVD and VCR manage to co-exist peacefully. They probably all have power-converters built-in, but I don't care.

But our two cell phones have totally incompatible chargers -- justify that! If something requires line-conditioning -- so be it. But most things do NOT require that, and those that do still not require a voltage converter of their own.

fairly standard supply voltages like 5V,9V,12V etc.

Exactly! Why 5V, 9V, 12V, etc.?! I also have 4.5 and 6 and the connectors are all of different shape and form. There is no reason for this diversity...

Re:DC power -- sad failure of standartization

[theLOUDroom]

You are just arguing for the sake of arguing, aren't you?..

Nope. There are real reasons why you don't want to jumper the DC supplies for everything on your desk together.

Somehow, my vacuum cleaner does not screw up my washer nor drier. My lady's hair-drier does not affect our microwave, and our DVD and VCR manage to co-exist peacefully. They probably all have power-converters built-in, but I don't care.

You would care if your VCR flipped out every time the washer was on.
Of if turning on your printer lead to an undervoltage situation that fried your scanner.

But our two cell phones have totally incompatible chargers -- justify that!

My cell uses lithium polymer batteries. My gf's uses ni-cad. This results in different cell voltages.

Re:DC power -- sad failure of standartization

[gregmac]

Actually, its more like Philips Screw drivers, and Flathead.

Flathead screws are probably the worst invention ever. Philips aren't much better -- mostly because they wear easily.

Some day you americans will see the light and start using robeterson.

That said, Fuller makes an awesome 7-in-1 screwdriver that contains #1 and #2 robertson, philips, flathead, and 1/4, 3/8, and something else driver bits. All on one shaft that is reversable, with reversable bits on each end. I almost* always have it in my toolbelt, and it's probably the most useful tool I've ever owned :p

* almost always, because a couple of days ago someone in the office stole mine. When I find out who it was I will be introducing their fingers to a pair of vice grips.

Re:DC power -- sad failure of standartization

[mi]

You are making no sense. By your logic, because each device's needs are uniquely different, we should not even have standardized the AC supply. Every device should instead be packaged with a little diesel, gas, or oil generator producing the electricity to the exact specifications of the maker. But even that would require standardizing on some sort of fuel... And certainly -- by your logic -- since no fuel will be optimal for all devices, we'll need them all. Of several "fairly standard" grades of quality, of course.

Fortunately, this is not the dominant point of view and the existing AC standards strongly encourage the manufacturers to design their products to work with them.

There are real reasons why you don't want to jumper the DC supplies for everything on your desk together.

My VCR and DVD are "jumped together" -- as is the TV. What is the reason, I don't want that, again?

You would care if your VCR flipped out every time the washer was on.

I would, but it does not -- that is the point. Ever been to a laundromat? How do 4 TV-sets co-exist with 20 washers and 12 driers -- which are always on?

My cell uses lithium polymer batteries. My gf's uses ni-cad. This results in different cell voltages.

It does not have to result in different voltage -- 5 or 10% of extra capacity (if that) is not justified by the extra brick. This is moot anyway since, a DC-to-DC converter is much smaller, so there'd be no need for the heavy "bricks" required for the AC-to-DC conversion.

As the lovers' portraits get longer on the breasts of aging women, so will this discussion increasingly embarass you, as more and more devices begin using the power-over-etherner and/or power-over-USB (like Blackberry does already) to work and to charge their batteries.

Re:DC power -- sad failure of standartization

[theLOUDroom]

You are making no sense. By your logic, because each device's needs are uniquely different, we should not even have standardized the AC supply.

Not true. What I'm saying is that there's not a lot of benfit to forcing things that have already standardized on AC power to re-standize onto DC power. You will still need a "brick" to convert to power and to filter it for each device AND you're going to need a NEW brick to convert your AC to DC.

My VCR and DVD are "jumped together" -- as is the TV. What is the reason, I don't want that, again?

You're ignoring the fact that I said DC!

As the lovers' portraits get longer on the breasts of aging women, so will this discussion increasingly embarass you, as more and more devices begin using the power-over-etherner and/or power-over-USB (like Blackberry does already) to work and to charge their batteries.

All this talk by boobs about boobs isn't going to change that facts you're ignoring.
If you want to be willfully ignorant of power supply filtering, wattage, battery technology and a whole mess of other issues, that's your deal, but don't expect a bunch of electrical engineers (like myself) to listen to you.

Do you realize how retarded it is to use POE for something that DOESN'T NEED ETHERNET? You're using 2 pairs out of the whole damn cable and you're paying for signal quality you don't need. Maybe you're even paying for ethernet hardware one the other side of the cable you don't need.

The same applies to USB, except it's even worse because you're limited even more in power, the cable is even more expensive, and you'll probably be violating the USB standard. (Don't expect manufacturer of electic razors to shell out for interface chips that broadcast "I am an electric razor".)

The real fun will start when your new "USB-powered" speakers start demanding multiple ports to get the necessary wattage (or "special" high current ports). Then you'll need even more ports than you have devices :)

That explains the RJ45 on my Braun

[Anonymous Coward]

Well, no it doesn't really.

X10 camera

[Anonymous Coward]

Didn't X10 cameras already do that? The transformer doubles as a networking device, allowing a central unit to control all cameras. Ok, so it's not the same as the ethernet, but this is kinda old already...

Work hazard

[Ceriel Nosforit]

There goes the only type of devices I don't repeatedly electrocute myself on. =(
Damn you! Damn you to heck!

Re:Work hazard

[Anonymous Coward]

Yeah, I hate when my USB devices shoot me across the room trailed by lightning.

This is how the matrix gets started

[Anonymous Coward]

Before long they'll be embedding an RJ45 jack in your skull and making you fatties hit the treadmill to power your own lan parties.

cool beans!

[blew_fantom]

we're so behind in our infrastructure build-outs as compared to say, south korea, this would be a cost effective and perhaps efficient way to either retrofit buildings to be 'smart buildings' or to build new offices and buildings with such infrastructure. now, if they can only get PoE to my IP-based coffee maker and toaster, i'm all set.

Re:cool beans!

[Anonymous Coward]

In South Korea, ...

Oh, never mind.

39 W is Enough for Whole Village in India

[Anonymous Coward]

Couple this article with an older Slashdot article about bringing cheap broadband into remote villages in India, and you soon realize that the Ethernet cable could be a way to bring electricity into remote Indian villages that do not have electricity. You may say, "Well, this is ridiculous." This proposal is no more ridiculous than spending billions of dollars on high technology (e.g. GPS, cheap broadband, and others) to fix the SYMPTOMS of fundamental problems with Indian culture. No one wants to address the problems themselves (e.g. aborting female fetuses) because addressing the symptoms is more politically acceptable.

Admittedly Indian culture is somewhat better than Chinese culture, but we are really scraping the bottom of the barrel here.

Re:39 W is Enough for Whole Village in India

[Grishnakh]

No one wants to address the problems themselves (e.g. aborting female fetuses) because addressing the symptoms is more politically acceptable.

What's wrong with that? It seems like a problem that will resolve itself. Everyone aborts their female children, the villages have only males, then within one generation there's no more children at all. All the men will either spend their lives alone or leave for someplace else. In the end, the villages will become abandoned, and the animals can take over.

The only bad part is that we can't force people to stay in these villages, and reap what they sow. It's too easy for these extra males to leave and move to other cities or countries.

This reminds me of a religious movement in early American history. I believe it was the Calvinists, but I'm not absolutely sure. Anyway, they thought that sex was really horrible, and so they never did it. Pretty soon, the movement was gone, since they never got any new members for some odd reason... something about children not appearing without sex...

Re:39 W is Enough for Whole Village in India

[saintlupus]

I believe it was the Calvinists, but I'm not absolutely sure. Anyway, they thought that sex was really horrible, and so they never did it. Pretty soon, the movement was gone, since they never got any new members for some odd reason... something about children not appearing without sex...

The Shakers.

They thought that only adults capable of rationally converting should be part of their religious community. Seems pretty advanced to me.

--saint

Re:39 W is Enough for Whole Village in India

[psetzer]

Well, since your Indian village can only be 100 meters away from a repeater, may I suggest a really damn long power cord? Or are you talking thicknet, where you could go a whole quarter mile before you need a repeater? Yeah, let's put a friggin' router in every village. That shouldn't cost us too much.

Re:39 W is Enough for Whole Village in India

[jmenezes]

There were a few movemnets like this, but the most prominent one that sticks in my head is the Shakers.
To help them avoid the "evils" of sex, they would have sessions where they all gather in a room, and pretty much just shake, shaking the evil thoughts and needs out of their body.
The main that they kept the society going was the adoption of orphans, as very few people willfully joined the society.
At the turn of the 20th century, there were fewer orphans in the surrounding areas to bring to the lifestyle, therefore the society as a whole died out

I think you mean Firewire is the next USB

[2nd Post!]

Since Firewire has support for:
IP for 1394
Power over Firewire
Mass storage

But at some point you have to hook up a wallwart to get power somewhere...

Re:I think you mean Firewire is the next USB

[bdcrazy]

You could locate a power converter next to or near your servers and or your root hub. This would put it out of the way and eliminate the need of additional wall worts as long as you buy devices that can use this power.

Re:I think you mean Firewire is the next USB

[Anonymous Coward]

Yeah.

We have one of these switches...

[Anonymous Struct]

...but we just use it to set users on fire.

Re:We have one of these switches...

[hobbesx]

...but we just use it to set users on fire.

You'll find it also works well for behavior modification:

Tech: Support, how can I help you? (Or, alternately: WHAT!?!)

User: Uh- My printer won't print, and I don't know how to make it work... It says 'Use printer offline'

Tech: (sound of rapid keystrokes)

BwwaaaZap!

User: Yeowch!

User: I, uh... I think I'll type it out.

Tech: (click)

amperage and death

[MORTAR_COMBAT!]

well this random post seems to claim that 1 mA can kill a sick person, and 100 mA can kill a healthy person... so my "an amp can kill a person" should actually say "an amp could kill 1000 sick people... or 10 healthy people... or some combination thereof..."

Great for wifi access points

[Technonotice_Dom]

I've seen this implemented in a local school (in the UK) that issues all staff with laptops. The laptops then have a student register application running on them, and the staff can wander across the building using it. They've put up lots of D-Link access points scattered all over their buildings, just mounted to the wall on wooden boards - an ethernet cable appears out of the wall, or from a socket, into a little box (size of PCMCIA card, but thicker) which then has two cables (power + ethernet) going into the access point.

Appears to work very well for them.

39W, Bah!

[VernonNemitz]

You can trickle-charge your electric car on only 13W, if you are willing to wait long enough!

Re:Why I HATE You All!

[confusion]

There are only 2 industries that call their customers "users". One is IT.

Jerry
http://www.syslog.org/

This just in...new energy source

[Anonymous Coward]

to be developed DOE research program. Bush administration heard "there was unused wires in the ethernets". Goverment spokesperson from DOE: "The problem of where to get the energy that will make the hydrogen ecomony work is one of the president's top priorities. We have been directed to develop new technology that can split water into hydrogen and oxygen using low amp 48v DC power. Such DC power sources are all around us and we just haven't been using them."
Reporters have obtained documents showing there is already one research grant proposal from a group of scientists who used to work for Enron.

I know its a troll but you just never know what a /. story will bring to mind!

real world problem

[Anonymous Coward]

...but the demo shows how creative, out-of-the box thinking can solve some real problems for our industry.

is the funnies part for a LAN connected razor

Rexec??

[hajihill]

rexec -l username -n password razor shave -uname user

encrypted bidirectional RFID and physical access?

[neonman]

I'd love to see PoE used for encrypted bidirectional RFID readers and physical (door) access control. Each door would require only one UTP cable, providing power for both the reader and the door strike. I'm not sure how this would apply to magnetic locks.

The less parallel wiring a building needs the better.

Such a product would also enable the battery backup of an entire building's access control system - a single UPS for the ethernet switches.

Networked sex toys?

[Anonymous Coward]

The whole battery thing was always a drag.

POE changes everything.

When will I need to hire an electrician?

[Shishak]

To install my Network cable because it all has to be properly installed/grounded etc. now that it is carrying electricity?

The electrical union must LOVE PoE they have been trying to get state electrical code written to include low voltage wiring for years, maybe PoE will be enough to get it changed :/

Re:When will I need to hire an electrician?

[jeffo_7]

I think there are a few points that everyone is forgetting (or don't know about). I'll try to clear up as many misconceptions as possible that people are getting hung up on.

1) Power over ethernet is dangerous to people that touch the bare wire

This is not true. PoE uses voltages that are considered (are in the class) 'very low voltage'. If a person comes in contact with a power wire at this voltage, it is harmless because the resistance of skin doesn't allow enough current to flow (remember V=IR, therefore I=V/R and since R~1kohm, I is relatively small for small voltages). This is not to say that someone wouldn't feel a shock, but feeling a shock doesn't make it dangerous (think of when you get a shock after taking off a sweater - you don't get electricuted, just a discomfort)

2) It has been mentioned that electricans might have to install it because 'it carries power'. And that it has to be 'properly installed/grounded'. This doesn't really apply, since currently, anyone can run speaker wire (ie for surround sound) that carries power (up and beyond 100W). We're talking about up to 39W here. Secondly, regarding the proper installation/grounding. Well, it is good practice to install anything proper, and as for grounding, it doesn't really apply here.

2b) an extention of 2, although the electrical code doesn't have much to say about low voltage, there are some things it does. For example, it states that a low voltage junction box cannot contain high voltage lines as well. If the two types of outlets are to be placed next to each other, there must be a barrier between the two sections. TIA/EIA (Telecommunication Industry Association) takes care of most low voltage code stuff (although inspections are not required for low voltage work).

3) P=VI (for DC)

High power devices cannot be run from PoE. Since UTP is 22 guage (maybe it's 24), it cannot handle large currents, and since the voltage has to be kept low for safely reasons, you cannot power high wattage devices from PoE. PoE was never designed to run a coffee maker - it was designed for such things as wi-fi access points.

4) PoE will damage non-PoE aware equipment

While this could be true for some equipment, it is not the general case. If PoE runs on +12V and the ethernet card is expecting +5V (that's what ehternet uses for it's communication), the card may have sufficient protection to limit the +12V and no damage will result. Although this would be a vaild concern because NIC manufacturers try to cut every corner.

5) Normal ethernet does not carry power

This is technically false. Back to ohms law and power equations:

P=V^2/R

In order for power transmitted to be 0W, either V=0 or R=infinity. Since V=+5V at some time when connected, and the impedance of the input to the ethernet card cannot be infinity, there has to be some power being transfered (although very little).

6) It was posted earlier that an AC shock is less dangerous than a DC shock. This is the exact oposite! When you are being shocked with an alternating current, you are 'stuck'. This is because your muscles operate by electric current, and since your muscles are sensing the alternating current, they oscillate and you cannot control them. When you are shocked by a direct current voltage, you have control over your muscles (and depending on the polarity of the voltage, you might even be 'kicked' away from the conductor that is shocking you).

39W no use for Prescotts

[kompiluj]

For my brand new Prescott based computer I need at least 390W :)

Re:39W no use for Prescotts

[Anonymous Coward]

Just use ten ethernet cards.

internet radio?

[the_2nd_coming]

this could be cool for an internet radio appliance or many other small single use internet appliances.

I'm waiting for the opposite

[Z00L00K]

What I would like to see is LAN over Power, which would bean that I could monitor the coffee machine from a distance without extra cabling.

Re:I'm waiting for the opposite

[KevlarTheSleepinator]

they already have http://www.hometownconnections.com/utility/broadba nd.htmlwhat you seek

My toaster

[Anonymous Coward]

I want enough power to run my linux toaster.

obvious extension

[room101]

Can't wait until power over wireless connections become available.

then you'll really have something.

Re:obvious extension

[Maljin Jolt]

Nicola Tesla already invented power over wireless in 1908. His invention was scratched, because having wires mean to control energy distribution and money.

However, with an array of properly tuned antennas, you can already draw significant amount of power (somtimes in order of watts) from near cell phone towers, radio stations, radars, until you get caught by team equipped with proper field gradient measuring equipment.

Anyway, using modulated signals as a source of power somewhat reminds me of burning books just for heating.

What about 1 gig ethernet and 10g?

[Anonymous Coward]

1 gig and 10gig (2007) both use all 4 twisted pairs. How do they expect to power the devices of the future?

Re:What about 1 gig ethernet and 10g?

[Anonymous Coward]

POE can use either the used pairs or unused pairs. IE -you don't need to have free pairs to carry power.

I'd also like to point out that there is no such thing as an ethernet cable. Ethernet is an OSI Layer 2 protocol. Category x cable is the correct terminology.

Re:Why I HATE You All!

[SpecBear]

Yeah, and in every other industry we're called "consumers." What's your point?

Wireless Power

[EqualSlash]

Don't send it in the form of electricty..send it in the form of radiation energy just like how the Sun provides us energy wirelessly. Even NASA tested a Laser-Powered Aircraft last year.

Re:Wireless Power

[Anonymous Coward]

News to you: EM radiation is EM radiation. Light is also EM radiation--just magnitudes more energetic than you associate with radio.

Also, to us really white people (I'm practically an albino--e.g. Irishman) exposure to the sun isn't without risks.

Re:Wireless Power

[Calroth]

Don't send it in the form of electricty..send it in the form of radiation energy just like how the Sun provides us energy wirelessly.

The problems with this are:

1) It's not hugely efficient with our current technology... the Sun provides us energy wirelessly, and our current photovoltaic cells are expensive and are 1-2% efficient (could be higher by the time you read this). There are other technologies, but they don't provide huge amounts of energy either, which leads us to...

2) If you increase the power, it becomes a hazard to anybody who walks in its path. Sunlight is hazardous enough; you don't want to get microwaved, burnt through with laser beams, etc. etc.

Re:Wireless Power

[Anonymous Coward]

Dude, get with the times. Photocells were 1-2% efficient when they were FIRST made--back in the 70's or so. Standard cells are 10-12% efficient NOW. Yeah, that's not especially huge, but it's still about a hundred watts/m^2 at the equator.

Re:Wireless Power

[uglyduckling]

our current photovoltaic cells are expensive and are 1-2% efficient (could be higher by the time you read this)

Does this mean that you're in the middle of inventing a new, much more efficient, cell? Exciting...!

What...

[fizban]

...is the world coming to?

Power over ethernet! Internet over power lines! Human sacrifice! Dogs and cats, living together! Mass Hysteria, people!

Re:What...

[wwahammy]

Nothing like a good Ghostbusters reference :)

Mayhem and chaos!

[DaveJ2001]

Power over ethernet? Bah! Here's a few more uses for power over anything!

Ethernet Enabled Electric Razors?

[Tezkah]

I'd really like to see an electric razor that had a version of Windows on it. You'd be shaving your face, and then a holographic Clippy would pop up: "It looks like you're shaving your face, would you like tips on shaving your junk?"

I'm pretty sure that should be the prompt he'd give you no matter what you're shaving. "It looks like you're shaving your head, would you like tips on shaving your junk?"

Re:Ethernet Enabled Electric Razors?

[aonifer]

Then it downloads a worm and cuts your head off.

Re:Ethernet Enabled Electric Razors?

[Anonymous Coward]

Clippy: Here's a tip - If you wax your junk then you won't have to shave it for a long time!

Re:Ethernet Enabled Electric Razors?

[Drakonian]

Which one?

Re:Ethernet Enabled Electric Razors?

[Anonymous Coward]

I just have to add my comment - I couldn't fall asleep last night, 'cause I thought of this post, and laughed for about 15 minutes straight. My girlfriend kicked me out of bed. :( Thanks a lot! (the laugh was great)

Someone has to say it.

[mad.frog]

Imagine a Beowulf cluster of electric razors...

ok, sure "Well, this is ridiculous"

[rednip]

you soon realize that the Ethernet cable could be a way to bring electricity into remote Indian villages that do not have electricity...

I've got an idea that's even lower tech, just run a lampcord out. Then you can use the normal plugs...

You don't have to be an EE to know how stupid it is. If you think house cats can do some damage, just wait until your powere gets chewed up by a lion. All kidding aside, the longer the run the more loss of power, ethernet cables don't have the kind of sheilding needed for long distance transmition of power (by a long shot). Also remote villages have no infrastructure to the power plants (ie. 'telephone poles').

Re:ok, sure "Well, this is ridiculous"

[SpinyManiac]

You mean chewed by a tiger.
You get tigers in India and lions in Africa. Possibly even in Kenya.

Lower cost per AP

[ccbutler]

earlier this year I converted our warehouse of 250,000 square feet to 802.11b WiFi using Cisco 1200 series AP's. Our cost per AP was 1900.00 (CDN) using power over ethernet. This cost includes contractors, electricians, cat5e, fiber, and even antennas. Im not here to toot any horns for 802.11b or Cisco or anything... but our cost per AP would have been WAY higher if it weren't for power-over-ethernet technology.

Re:Lower cost per AP

[tomhudson]

... and now anyone can knock out your wireless network by jacking a second power-drawing device into your ethernet cable ... 13 watts isn't much to play around with.

Re:Lower cost per AP

[ccbutler]

well there are much easier ways to knock out an AP using software, and you won't even get your hands dirty.

More importantly tho, if you can't even physicaly secure your WIRED network, you really are not doing your job.

Re:Lower cost per AP

[dknj]

your ethernet cables do run through the ceilings and walls to your secured network room, right? and you have security cameras to make sure joe blow doesn't walk in with a 10ft ladder to mess with said cables.. right? ok, just checking.

-dk

Re:Lower cost per AP

[tomhudson]

• Cabling in ceiling? Check.
• Cameras (connected to DVR with remote capability? Check.
• Under lock and key? Check.

So, would I trust it being secure. No fucking way.

Truisms of Security

1. Nothing is completely secure.
2. Nothing can ever be made completely secure.
3. Idiot-proof solutions aren't because idiots are such geniuses at fucking things up.
4. If you think you've thought of everything, you've just become one of those idiots.

Just a thought ... :-) You're welcome to add to the list.

Re:Lower cost per AP

[Anonymous Coward]

So, you're the guy who maintains the MAC address spreadsheet for every device on the network? Or are you just talkin' shit?

Re:Lower cost per AP

[tomhudson]

Don't use spreadsheets. Haven't used one in at least 5 years.

Re:Lower cost per AP

[dknj]

What are you talking about. I was saying, if someone can unplug your ethernet access point, then YOU have bigger problems to worry about. We can guarantee the safety of our wireless access points. As soon as one is unplugged, we are alerted. If we see that the AP has been unplugged, we can check back over our DVR and prove it was tampered with/stolen/whatever and pursue appropriate action.

Now if you would be kind enough to return to the original topic and reread your post, you are saying someone can tamper with your access point. Whats to say someone can't tamper with a switch thats in the same location? The only thing you have done is removed the need to call an electrician in to run power to arbitrary locations. Maybe you don't have to worry about budgeting, but some places do and electricians can get pricey depending on the job and the number of receptacles needed

-dk

Re:Lower cost per AP

[jonoton]

Cisco & Power over ethernet, now there's a combination to make my blood boil....

Just 'cos Cisco's "Phantom Power" was rejected by IEEE they sort of threw their rattle out of the pram and aren't supporting 802.3af on their ip phones for at least another year.

Fantastic....

Fortunately rather than lose the order for a few hundred IP handsets they've agreed to supply Powerdsine modules with each phone so we can power them off non cisco PoE switches.

Re:Lower cost per AP

[tomhudson]

According to the standard, the max. power supplied is 13 watts. All I have to do is plug something in anywhere along the line that draws a few watts and you're out of business, and I can do this without anything more complicated than an xacto knife - I don't even have to break the circuit.. Now you've got to trace all the cabling to find out where I've added my resistor.

How much do you want to bet that, instead of fixing it, it would be cheaper to run a separate low-voltage (12v) line and/or solar brick (solar cell + battery) than to take the time to fix it?

Re:Lower cost per AP

[dknj]

Well, I'm sorry for having a pointless conversation with you. You obviously know everything there is to know about setting up wireless access points. I'm also pretty sure you know that every building is designed the same. And as for people who actually use cable conduits in their ceilings, i'm sure they readily label each cable as it runs through so they can quickly sift through 500+ cables to find the one that is powering a wireless access point. If you'll excuse me, this will be my last reply.. I have better things to do than argue with trolls

-dk

Re:Lower cost per AP

[tomhudson]

And as for people who actually use cable conduits in their ceilings, i'm sure they readily label each cable as it runs through so they can quickly sift through 500+ cables to find the one that is powering a wireless access point.

Some older buildings have layers of wire a foot thick - it's almost always cheaper to lay new on top of the old stuff rather than figure out the rats' nest of wiring.

Re:Lower cost per AP

[IncohereD]

Some older buildings have layers of wire a foot thick - it's almost always cheaper to lay new on top of the old stuff rather than figure out the rats' nest of wiring.

You think that's bad, check out the downtown central office of the phone company in one of your older cities. It's only trouble when the floor is starting to crack.

pow

[ericpearl]

I'm waiting for power over wifi.

Electric razors?

[RealAlaskan]

Bizarre uses include electric razors.

I'm trying to think of places where I have seen an ethernet jack but no wall power. Hmmm .... zero. Never seen such a place.

Now I'm trying to think how many times I've wanted to shave in a room which contained an ethernet jack. Hmmmm .... zero.

So, come on, somebody, tell me why you would buy a power-over-ethernet razor. I'm stumped.

Re:Electric razors?

[Drishmung]

On the other hand, if you've every travelled outside North America, you've probably seen a wall socket into which your razor would not plug (without an adaptor). http://users.pandora.be/worldstandards/electricity .htm, http://www.powercords.co.uk/standard.htm

Now, imagine a universal, world-wide standard for low power devices. Would that be useful?

Re:Electric razors?

[RealAlaskan]

... imagine a universal, world-wide standard for low power devices.

How about the AA cell? Would that be useful?

Re:Electric razors?

[Drishmung]

Does your razor take AA cells? Or AAA, or C, or, ...

Re:Electric razors?

[Anonymous Coward]

... tell me why you would buy a power-over-ethernet razor. I'm stumped.

To get more girls ... Remember the stats for shaved men vs. unshaved ...

Re:Electric razors?

[ManxStef]

Well I can hazard a guess as to why some people might buy something like a, uh, razor or electric toothbrush... after all, somebody out there must have a use for devices such as this "Eye Massager", otherwise why would they make them?!

Re:Electric razors?

[Anonymous Coward]

I'm with you. Also, it will be real nice to power laptops off an Ethernet jack.

Re:Electric razors?

[Anonymous Coward]

Very simple: ground loops or power surges. I live in an area subject to all kinds of electrical/lightning disturbances. I have a bunch of Polycom IP 600 phones at home for use with Asterisk. The phones support PoE as well as a standard wall-wart power supply. By powering the phones with PoE I can guarantee that my APC SmartUPS SU1400RMXL and another better surge protector are powering all loads and there is no way for a surge to creep into the system. (I also have a whole-house transfer switch to switch whole rooms to the APC SmartUPS)

You may laugh, but surges always divert to lowest electrical potential (i.e. ground), which might be a seemingly harmless serial connection or an ethernet connection...

Re:Electric razors?

[Anonymous Coward]

What? Haven't you ever shaved while crawling through an attic crawl space while mounting wireless APs?

Re:Electric razors?

[identity0]

I am currently trapped inside the server room of my company, condemned to stay until I fix our 2 million lines of perl code that runs our trash compactor. I have been here for seven months, and have not been able to shave, for I cannot unplug any of our servers to plug in my electric razor.

I shall welcome this miracle of technology which will allow me to be free of body hair.

Does anyone know if they're going to make a coffee maker on ethernet power?

Re:Electric razors?

[b0s0z0ku]

Now, imagine a universal, world-wide standard for low power devices.

Actually, there is a standard 12V outlet design used throughout the world. It's called a car cigarette lighter socket, and it can carry 10-20A without melting, unlike Ethernet cabling, which would probably catch fire quickly.

-b.

Re:Electric razors?

[Anonymous Coward]

Does your razor plug into ethernet?_

Re:Electric razors?

[Frogbert]

I don't know, people are pretty stupid when it comes to power. I know of people who bought an Xbox in America (for a bargin price of $150 or something) shipped it to Australia (more expensive), realised it couldn't fit into Australian powerpoints and did the most natural thing any person would do.. bend the plug until it did fit. Long story short, big bang and a dead, expensive, US Xbox.

Re:Electric razors?

[Drishmung]

Hey, we have to find a use for all those IPv6 addresses somehow.

To some extent, it does not matter whether or not the razor is networked. The prospect of a universal power supply standard (that happens to provide networking) is interesting in its own right.

Re:Electric razors?

[Drishmung]

Very good point.

Re:Electric razors?

[bunkpariah]

come on, somebody, tell me why you would buy a power-over-ethernet razor

It's the most convenient way for me to remote-shave your wife.

Power over USB

[elhaf]

The usb spec already provides a certain amount of power to drive things like small gameboy lights or memory stick readers, but these don't always work. For instance, you sometimes have to get a Powered USB Hub just to drive devices such as card scanners. And then you have to plug that in.

ethernet cabling???

[Anonymous Coward]

I'd like to point out that there is no such thing as an ethernet cable. Ethernet is a layer 2 (OSI) protocol not a type of cabling.

Video Over Cat5

[SLOviper]

For my church projector setup, we're planning to use a Cat5 video extender to get a signal to a couple ceiling-mounted projectors. Obviously, the projector itself needs its own power, but the box that translates the cat5 signal back to DB15 needs its own brick as well. I've looked, and after looking, dreamed for a device that uses PoE for a video extender. Perfect application IMO.

Also beneficial for those doing KVMoE.

Re:Video Over Cat5

[Anonymous Coward]

Isn't Jesus enough these days?

Old people....

[mrn121]

That's nothing. In Korea, old people can read email on their electric razors.

Juxtaposition, eh?

[BigDawgES]

So now we're working towards transmitting internet through our power lines, and power through our internet lines.

HAM & Military Radio Interferece

[Anonymous Coward]

I know that Ethernet via power lines (the flip side) interrupts radio frequencies on military and civilian bands.

And this would be the same, except for less power so less interference. But I'm clueless on the topic. Does anybody not clueless care to comment?

PHB alert!

[nekoniku]

How long after PoE becomes a reality before some PHB tries to re-heat his coffee by dipping the ethernet cable into it?

ethernet over power

[akb]

I would much rather have devices support "ethernet over power" than "power over ethernet". That would cut the cost of rewiring buildings substantially and you wouldn't have to worry about the low power available w/ PoE. Unfortunately, the powerline network products I've seen aren't nearly fast enough.

For the average person, running ethernet cable into the den for the Tivo-like thing that has a network port is bad news. There's already cabling in the den, and every room of the house, for power, it makes much more sense to use that.

Let's hope powerline products improve.

Does this change things with the electrical code?

[Quimo]

Currently (in my area Ontario,Canada) ethernet cabling qualifies as a low voltage cabling and while there are installation requirements no inspections are required for said wiring. Any ideas on how this would change things. To me it sounds like the wiring may no longer be low voltage when POE is in use.

Backup Power Supply

[KrackHouse]

Had an outdoor wireless router power supply melt which caused a major outage. The out of production power supplies were a tad hard to find so we just used the POE adapter and it's been running fine ever since.

solar-power satellites, crystal radio, RFID

[davidwr]

Solar Power Satellites, the early-days crystal radios, and RFID-tags are all examples of what you are talking about. Sure, it's not 802.11, but it's still power over the ether.

Dare I say it? "All your cancer are belong to us" :)

Sounds useful but...

[madamewebb]

I guess it depends on how it's implemented but it sounds like it might be useful especially for all those little items that each have there own charger, if they all charged up over ethernet then it would make things simpler. Would be nice for ethernet printers and mp3 players with server function if it could provide enough power. And lets not forget eletric toothbrushes too...;)

get it right!

[Anonymous Coward]

internet goes on the internet wire, ethernet goes on the ethernet wire. Get it right. :)

Re:Why I HATE You All!

[Anonymous Coward]

Uh, I hate to take on the role of Captain Obvious, but his point was that the OTHER industry that calls their customers "users" is the (illicit) drug industry.

Thus sparking more creative minds to muse about the similarities between the drug trade and the IT trade.

Or something.

Power over LAN is outdated. Power over WLAN rulez!

[erichschubert]

Power over WLAN is WAY better than old PoE.
See, it's written PoWer, not PoEr (even if some may pronounce it that way), isn't it?

P.S. Slashdot sucks, since you can't read it with Mozilla. Why can't they fix their HTML? Fortunately there is AlterSlash.

Too many unmarried men leads to war

[ulatekh]

All the men will either spend their lives alone or leave for someplace else.

Actually, the sociological research I saw (wish I remembered where, sorry) indicated that having a nation with a large number of unmarried men without real prospects for marriage strongly correlated with that nation going to war.

The Middle East is in a state of semi-permanent war. India keeps butting heads with Pakistan. China may have designed the 9/11 attacks, and in general certainly seems bent on regional domination, if not world domination.

To think that women's rights really are the key to world peace...it boggles the mind...

Re:Too many unmarried men leads to war

[I_Love_Pocky!]

To think that women's rights really are the key to world peace...it boggles the mind...

But do the ends justify the means?

Just imagine a Beowulf cluster....

[gmletzkojr]

Sure. Just imagine a Beowulf cluster of razors....

no, YOU get it right

[Anonymous Coward]

Ethernet cast its net over the ether not the wire.

Why power over WiFi doesn't work

[Anonymous Coward]

Assume you want 5 watts of power at a working radius of 30m (100ft), and your receiving antenna cross-section is a 6x10^-3 m^2 (10 sq. inch, rather large actually).

Then you need to be broadcasting at 9.5 megawatts! And that's assuming 100% efficiency.

I want PoE, but it's stupidly expensive.

[adb]

Right now it triples the price of a switch. (Compare the 2626 and 2626-PWR, for example.)

So no.

What will they think of next?

[Flashpot]

Packet over Air?

Why would you use an omnidirectional antenna?

[adb]

If I were realistically trying to do wireless power, I would use a low-power signal to locate the target, then send the power in a tight beam.

This method has its own problems (caution: grotesque laser wounds), of course, but at least it's not physically impossible.

How about Audio over Power lines?

[dbretton]

It would be sooooo convenient for home theater owners to no longer have to worry about wiring the damn house up for the latest Dolby 19.1 digital surround sound.

Just plug the speakers into the wall and viola!

power + audio. :)

Re:How about Audio over Power lines?

[Fastolfe]

Seriously, wouldn't that be nice? Have the "speaker" be an ethernet digital audio receiver. You could flip a switch on each speaker telling it what speaker it was (left/rear, whatever), and it would simply listen for (or request) the audio stream it was interested in.

The actual receiver device could auto-detect the speaker configuration and adapt what it was sending accordingly.

Possible Uses?

[pete-classic]

Possible uses for Power over Ethernet

Finally convincing the fucking cat to not chew on the cables?

-Peter

Re:Possible Uses?

[pete-classic]

Oh, or bait for mynock traps?

-Peter

It's a cable you use for ethernet.

[adb]

Therefore "ethernet cable" is the correct terminology.

(This has been brought to you by the English For Engineers foundation. HTH, HAND.)

Re:It's a cable you use for ethernet.

[Anonymous Coward]

Nope - It's a cable used for a multitude of upper layer protocols. Ethernet being one of them.

Ethernet carries email (SMTP) - would you call it an email cable?

how long before

[minus_273]

this becomes like power over USB is now. heh i can just see reading lamps powered over ethernet.

it's available

[Anonymous Coward]

Home-power-line based networking is available. Try your big-box electronics stores or online.

The problems with ethernet-over-power are
1) transformers - getting past them
2) noise - susceptible to RF
3) privacy - it can leak into the airwaves

and
4) cost - other solutions are frequently cheaper

If none of these apply to you, go for it.

induction

[Anonymous Coward]

what about that induction stuff where stuff is powered just by sitting on a pad. that's "wireless power"

no more dual voltage!

[Anonymous Coward]

if this can be standardized, then there'll be no need for dual voltage power bricks for computers that are networked.

Obligatory GI Joe reference

[hal2814]

You mean like the B.E.T.? (It stands for Broadcast Energy Transmitter, but I think it's funnier to think of GI Joe and Cobra battling over control of Black Entertainment Television)

Re:Obligatory GI Joe reference

[Anonymous Coward]

Cobra commander was really Snoop dog? Fasssssschnizle my nizzle bitchizle.

LTSP?

[circusnews]

So how long before some one comes up with a mobo that will run off of this?

In large deployments, this could be very useful.

Do you need a license now?

[Anonymous Coward]

I know that currently an electrical license is not required to run cat 5 cable in my state (NC) because it is low voltage. I wonder if this will change that law.

Now that would be impressive

[3ryon]

Wake me up when they get it working over Wi-Fi ethernet.

I've used PoE in my small business.

[Anonymous Coward]

Interesting all the comments here about PoE. I wonder how many posters have acutally used it in anyway?? I personally am using it in my small business. About a year ago, we upgraded our phone system to a Mitel 3300 based IP system. Problem is these phones require power. They all have a power jack on them - and optional wall transformers. Problem was, these are "smart phones" and take like 90 seconds to boot. Also, I didn't want to have a simple power bump cause dropped calls. But running power and having UPSes out in remote warehouse locations was not an option. The vendor was already quoting a HP-2626 Procurve switch because of it's VLAN management. When I asked about using PoE to power the phones all from the network room, they suggested a seperate PoE power injector. But when I saw the price, I found that the HP 2626 -PWR version was the same amount more money as the power injector. So I purchased one of those and now have one piece of equipment doing both. It's much cleaner - and all phones are powered by the big rack UPS in the network room.

I've done some "playing" with that switch and I see it somehow detects that the ethernet device is able to handle PoE and then turns that on. You plug in normal ethernet devices it does not supply power to them. I'm sure this is specified in the 802.3af specification - something I've not had time to read! But I somehow doubt that this switch would cause any problems with old ethernet devices. Even if you are worried, you can log into the switch and turn the power on/off on a per-port basis. We even tried inseting a single port power injector down stream from this switch - and it then would not supply power to that port - and the injector was. So it all "just works" or at least from what I've found so far!

Re:I've used PoE in my small business.

[amrust]

We're using a Cisco solution for our IP phone system. We've had a problem lately with some phones (that aren't PoE, they're powered by transformer) wanting to throw stray DC voltage back across the Ethernet communications pairs. Still don't know what's causing it.

Power to the hackers

[EmbeddedJanitor]

So if your box get 0wned the lights go dim?

Peace on Earth. Purity of Essence

[hedley]

Other uses for PoE.

Re:Peace on Earth. Purity of Essence

[b0s0z0ku]

Other uses for PoE.

Is a CRM-114 Discriminator required at both ends of the cable to allow the power to pass through?

-b.

already works for cable chewing cats

[puzzled]

I lived with this chick that had a cable chewing cat some years ago. One day one of my college roomies stopped by and as we were talking kitty walks out and starts in on the phone line in the living room.

Mike looked at me, got the *biggest* grin you've ever seen, then whipped out his cell phone and pressed redial ...

Kitty rang, backed up, hissed, then bit the cable again just in time for the third ring. Now I liked that cat and I have a long hair tortoise shell of my own, but I sure was glad that Mike cured that cat of ripping up cables.

Re:already works for cable chewing cats

[Anonymous Coward]

Kitty rang

Are you sure kitty only chewed on the cables, and not ate the whole phone?

Variax Guitars

[Tetsugaku-San]

Already use a form of RJ45 thats 'gig' gardened and supplies power to the computer section of this modelling guitar.

More info here

Re:13W could be dangerous... amount of power?

[swordfishBob]

The amount of power in 13W is 13W.
Obstacles include cabling standards and qualities. To be classified as Extra Low Voltage, you need to stay under 42V d.c. and 60V a.c. so we're talking 250-330mA, meaning cable losses will be significant. Using multiple pairs to carry power would help.

Going above ELV means following LV cabling rules (ie general power wiring) except in certain circumstances involving current limiting. There is such thing as Telecommunications Network Voltage which does go higher than ELV for the sake of backward compatibility with millions of phones.

Regarding safety:
- phone lines already carry TNV which can give you a good tingle, but it's current limited.
- it's not just whether someone thinks it's ok, but has to meet applicable standards and laws.

Some uses

[owlstead]

Just to fuel your imagination, I've put in some nice uses:
- Networked camera's (more zooming, tilting and maybe even lighting with 39 W)
- Networked printers
- Home server appliances (my VIA EPIA runs great with DVD player and 3.5" HDD on 53W, it would run just great on 39W without the DVD player)
- Media players (MPEG4 & MPEG 2 layer 3)
- Downlink switches

And I do not have a clue why they never use this for PDA's. Use a common network plug to synchronize your PDA, and give the customer a nice powered switch or network adapter instead of those stupid cradles.

Currently the standard is mostly found in Remote Access Points. I would have put my access point (which is at the best place for RF, but not for cables) on power over ethernet, but these components are hard to find. Just putting 5 V and splitting it at the end does not seem to work, probably because of the distance.

Re:Some uses

[upsidedown_duck]

- Networked camera's (more zooming, tilting and maybe even lighting with 39 W)

Girl wakes up. "What...what is that light doing above my bed?!?"

Re:Some uses

[anty]

Obviously you are not aware of the amount of power a laser printer uses, especially to heat it's fuser element

I don't know about you, but..

[Myself]

... lots of smaller devices (PDAs, older laptops) draw under 20 watts. The wall-wart for the Vadem Clio (sitting right here) only puts out 11 watts, and that's enough to apply a mild charge to the batteries while running the device.

Around the time HPNA powerline ethernet came out, I waited eagerly for a laptop maker to announce an AC adapter which would also bridge the machine to the network. No such device ever emerged. I'd love to be able to curl up on the couch with a network-connected device and not worry about the battery. I'd be happy to drop an RJ45 outlet in the corner. Will someone make a device that'll use both signals from the same cable?

Being low-voltage, you don't need to call an electrician to move network cable around. Thank goodness. There are murmurs within the electrical industry of trying to legislate a change to this, be watchful and let your representatives know that low-voltage wiring is not hazardous and should remain unregulated.

One problem with PoE is deciding which device gives and which receives. Right now, the cable modem, the router/firewall, and the 8-port switch all have wall warts. With PoE this could be reduced to one, but which one? For a simple star layout, it's simple. I fear the mess of adapters isn't going to get much cleaner, however.

Cameras and APs are the obvious early beneficiaries of this. Another poster mentioned doorstrikes and cardreaders. How about motion detectors, thermostats, and other environmental sensors?

If the HVAC system is plugged into the ethernet anyway (Or just running back to the same wiring closet, even if it's on separate hardware) then let's toss the duct dampers and other controls onto the same system. Wire the whole building with one type of wire, run it all back to one place, and have flexibility later.

And since we're replacing all the building's auxilliary systems with PoE connections, how about overhead music / paging systems? Individually addressible bidirectional speakers would enable all sorts of talk-and-listen applications, as well as point control of which programs go where.

13 watts is also enough for things like cash register scales, receipt printers, barcode scanners, and the like. A lot of that stuff runs on USB now, which is great. I can see applications where remote scales might take advantage of ethernet's distance capability. Also consider that powering down the USB host takes all the devices with it, but with ethernet-attached devices, the network can still "see" the RFID scanner if the register takes a crap for some reason.

Things like JetDirect print servers would also benefit from wallwartlessness. Yes, decent printers have a slot they sit in and receive power from, but there seems to be no shortage of standalone ethernet print servers.

How about postage scales that print "electronic postage" from a company's central account? They're great, they never need recharging, but they still need a network connection /and/ a wall-wart.

And, dare I say it, credit card terminals? We'll just make the manufacturers promise not to transmit the card stripe data in cleartext. (ATMs use some serious encryption, why can't Lowe's?)

Re:I don't know about you, but..

[Anonymous Coward]

I happened to be reading the BOFH series and then read your post. Truly scary stuff. Just say NO!

Dual T Spans

[Transdimentia]

When you have to get alot of single spans into a cabinent with little space, just wire 2 spans into a single cable!

Power over laser

[mrand]

In #11109104, Cyryathron wrote
>>
>> What crazy things will they think of next?
>> Power over Ethernet?
>> Internet over Powerlines?
>
> Power over Wireless Ethernet
> POW!

How about power over laser?

In the 1991 through 1993, I worked at Electrospace Systems, Inc (aka ESI) and one of their main businesses were secure phone systems for the government, and the government wanted a phone that would survive a HEMP event. Since you can't have any electrical cables running in or out of the thing, how do you power it?

The engineers immediately thought of using batteries, but after realizing how much power it would take to power the phone, they looked for alternative ideas. Remember, this is back before 3.3V LVCMOS, so most electronics tended to be pretty power hungry.

Then someone came up with the idea to recover the power from the received laser light! Sounded like the perfect solution until they realized how much laser power would be required. If someone were to disconnect the fiber and wave it around the room, serious eye damage (and possibly property damage?) would have resulted.

They went with the battery packs. Small lead-acid, as I recall, that would last 2 to 4 days, depending on usage.

Re:13W could be dangerous... amount of power?

[Anonymous Coward]

I think you switched ac and dc around. 42V x sqrt2 =~60V. I think there may also be a requirement that maximum power stays below 100W even during short circuits. Not sure though, it's been a long time ago I needed this.

Or we could just use Firewire

[Anonymous Coward]

I'd rather just use Firewire.

- things like mass-storage, optical drives (and burners), cameras and webcams and camcorders
- more power than 39W (I've heard it quoted as 45W, 50W, and 60W. Either way, it's more than 39W, and much more than 13W.)
- you can run IP over it
- with the latest versions, cable lengths run up to 100m

I'm waiting for the day when rooms don't have huge old-fashioned 120VAC outlets: just a row of Firewire ports. Whip out your computer, plug it in, and you've got power and network.

And you could use the same interface everywhere: on an airplane or a train, just plug in a Firewire cable, and your laptop has power and internet.

Re:Why I HATE You All!

[SpecBear]

Yes, I realized that the illegal drug trade was the other industry begin referred to. I just think it's a fairly specious connection to make. Implying IT is like drug dealing because both sets of customers are labeled similarly seems silly.

At least try to work some humor in there somewhere:
There are two industries where all of the clients are assholes. Proctology is one of them.

Power my house this way

[Fastolfe]

Given that at least half of the crap I have plugged into my AC outlets in my home end up converting it to DC power, why haven't we seen a DC power standard for home use?

Power-over-Ethernet seems like it could be expanded to do so much more.

Teeny Tiny Packet Sniffers

[ReelOddeeo]

One design problem this would solve is how to power teeny tiny packet sniffers. Such packet sniffers would be smaller than a pack of cigarettes, and run Linux. They connect to an IRC at night waiting for a command to cough up any interesting passwords they sniffed during the day.

A purely hypothetical exercise, of course.

Until power over ethernet, one problem has always been how to you power these packet sniffers?

You can hide the sniffers in a suspended ceiling, sometimes, even inside the large wall jack junction box, or other places. Even insde of a switch or router. But they had to have a separate AC adapter aligator clipped onto or plugged into an outlet somewhere.

The sniffer acts like an ethernet-level bridge by day. Dutifully forwarding packets, and arps, etc. Therefore, hard to detect, only introducing some latency. It has no IP address, or even Mac address of its own.

By night, it pretends to be the Mac and IP address of some hapless PC that is "behind" it, but probably powered off. Even if the devide it masquerades as is not powered off, it can still forward packets that don't conflict with the port number it is using to talk to its master.

Now that the power issue may be solved, the only big issue left is the cost issue. These teeny tiny computers are still to pricy to deploy in large numbers.

Bizarre Uses?

[apikoros]

"Bizarre uses include electric razors."

set voice = "Crocodile Dundee"

Electric Razor? That's not bizarre. Vibrator! Now that's bizarre!

/set voice

Plus... it gives a whole new meaning to "/.ed" :-)

This technology doesn't exist? Really?

[That's Unpossible!]

Does 'harm' own a microwave oven?

Re:This technology doesn't exist? Really?

[Anonymous Coward]

You use your microwave to power your laptop? Amazing! You've just GOT to share with us how to do it.

Re:This technology doesn't exist? Really?

[Anonymous Coward]

You use your microwave to power your laptop?

No, no. The microwave is wireless.

Firt pictures

[Anonymous Coward]

First picture of compatible cable :)

Feedin' the Trolls

[Anonymous Coward]

GP is a troll. He keeps posting the same link (and anti-China stuff) over and over and over...

No, it's a cable used for ethernet.

[adb]

It could be used for Token Ring or phone service or KVM relay, but it's not.

Something else could be used for ethernet, like RG-58, but it's not.

It's used for IP and things on top of IP, but a whole lot of other things are used for that as well.

It's an ethernet cable. You use it for ethernet. Very rarely do you need more detail; when you do, you say it's Category 5e UTP or whatever. But in ordinary usage, it's ethernet cable. Deal.

Nikola

[glsunder]

Next week: Nikola introduces power over wireless Ethernet.

Next thing...

[MORB]

...USB powered appliances. Oh, wait...

Speaking of DC power ...

[b0s0z0ku]

NYC had 110VDC power in places until the 1970s - for all I know, maybe it still does. In the early 70s, my dad got a job as the caretaker of a church uptown. He plugged a TV into a normal looking outlet, which resulted in the smoke being let out of the TVs circuitry. It turned out that the outlet was DC, not AC, which caused bad things to happen to the TV's transformer.

-b.

Re:Speaking of DC power ...

[Anonymous Coward]

Edison first set up shop in NYC, and his system was DC. Of course, he lost that war to Westinghouse, and the whole rest of the country standardized on AC. It's entirely possible that very old buildings that were wired by Edison at the turn of the [last] century may still have had some DC circuits.

aQazaQa

Spock:do or do not, there is no try

[xtermin8]

how much earlier was the Star Trek quote before Star Wars II? It also sounds like it may originally be from Confucious or Lao-Tzu. To get back on subject, It took a long while for the industry to adopt USB- although the technology is in place, consortiums have to negotiate standard for anything like this to be adopted widely-- unfortunately.

Mythbusters

[Anonymous Coward]

Mythbusters had a good episode where they investigated the real potential to get electrocuted in a bathtub by dropping in an appliance.

The answer was basically yes, and the actual current required was low (6mA I think) but it had to go directly through the heart and that was only likely if your feet were touching the (metal) drain while the electrical device fell on your chest/upper body. Furthermore, of course the fast-blow breaker had to be circumvented. Lastly it was heating element devices (like hair dryers) plugged into AC wall sockets that proved most dangerous.

So I assume that 39W is not really a shock hazard per se, but I would worry about fire hazards ...

USB replacement

[Anonymous Coward]

The best reason to add power to ethernet is to obsolete USB. There would only ever need to be three kinds of conector on a computing device then: power, net and video.

Power over ethernet.

[meatspray]

But what I want to know is can I run ethernet over power on top of power over ethernet?

What I want to know is

[ScrewMaster]

can I run my sump pump with it.

SNMP ==

[The Fink]

Shaver Network Management Protocol?

Sorry. It was there.

Think USB. Would you want to run separate power?

[skids]

In fact, USB sucks
so I'm looking forward to PoE-based input devices.

Lights?

[mattr]

Would it be enough to run one of these? Its spec is 20mA at 3.7V (it typically runs off a car lighter or on 3 AAA batteries). I hate buying batteries but this would be great!

It is always so dark under desks where you have to do all the wiring changes periodically, and no matter how many times I vow to put all wires high on a wall I always seem to end up under desks tracing wires. It would be pretty useful if I had one of these led flashlights on the end of 10m of ethernet that I could plug into a hub for whatever reason.

I'd recommend one of those ribbon ethernets on a selfwinding spool but the cheapo one I had broke pretty quickly.

Picture of the USB Razor and USB Security Camera

[Xoo]

I noticed the article didn't link to any images of the USB Razor, but I seem to have found one, rather low res...
here's the link

Also, I found a decent image of the USB Security camera

Schick Internet Razor Released!

[Xoo]

The internet razor is here, and we got our hands on it first. The new I-Shick 1.0 is a welcome alternative to standard shaving, wax and depilatories that miss stray hairs.

Just shave your legs with the I-Shick and it memorizes your follicle patters. Then connect the Razor through a USB port or infrared to your PC. A 3-D model of your leg is uploaded to your own personal website where you can view it and a number of other leg-hair statistics. If you missed any hair, you can clearly see it on the internet.

Version 2.0 of the I-Shick will include upgrades such as armpit, face, and pubic mapping. Investing in I-Shick 1.0 and registering allows you to download ongoing software updates for a subscription fee of $9.99 per month. Free shaving cream is a gift with initial sign up.

At $2,019.99 for the razor and connectors, the I-Shick seems a little steep initially, but very comparable to the cost of laser hair removal treatments, without all of the trouble of leaving the house.

Rachel Bondi's original article :-P
Too bad its fake.... although I don't really need to shave my legs, there are some women who need to very badly.

I'd love to

[fasuin]

have my laptop get the power from the ethernet cable when it is connected to a wired lan. That will save me to bring the power adapter when I move from office to office, and to avoid me to un/plug two plugs each time I need to move around... And I'd love to see ONE standard for laptop power adapter...

f*cking idiots

[MikeFM]

Because people are f*cking idiots?

Who gives a shit if something that saves you time every day of you life has a small chance of shortening your life? The chances are that the time saved by using the cellphone will more than replace the time you lose by using the phone.

Related to this someone recently tried to convince me that eatting microwaved food gives you cancer. As with the phone issue I told them I didn't give a f*ck.

If you live your life worrying about every little thing that could be harmful then you're not really living anyway. Enjoy life and don't be afraid of death.

PoE: Product already available (patent pending)

[Anonymous Coward]

Nice, elegant, right on time for xmas. Pic at http://lom42.free.fr/images/EthernetKiller.jpg

Tesla & wireless power

[AstroSurf]

But isn't it time for power over wi-fi?

No! The time for wireless power was a century ago. The brainchild of Tesla, the man who invented the 20th century (and some of the 21st, no doubt).

But we don't have it today because radiant power is to difficult to meter and bill. Because in the modern age, the only essential benefit of anything is that it pays. But worry not, soon enough we'll be billed for it whether we use it or not (or whether it's provided or not).