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Switch On For Powered Data Networks
ReLik writes "The BBC has an article regarding power supply via networks. 'Instead of needing adapters, computer networks could soon be supplying the devices they interconnect with both data and power. Some makers of network equipment are already putting the power via data cable system into their products. The basic plugs for computer networks are the same all over the world, raising the possibility that powered data cables could become a universal back-up power supply.'" We've talked a little about specific 802.3 spec advances previously.
... he'll re-define the term "firewall"
I wonder if they'll be sending it as straight binary or xml.
Both HIGH SPEED/POWER, AND FULL SPEED/POWER... and the as-yet-unreleased LUDICROUS SPEED/POWER.
This is just another case of the Brits trying to steal our momentum... those bastards.
Black and grey are both shades of white.
states that if you rub two sticks together you get fire.
Seriously, how long have did it take people to release there is a current in their ethernet cable? I known of products (home made and retail) that have been around for years that utilise this power supply.
How effective would this in a world striving to move to wireless protocols?!
It wouldn't get the chance to make a scratch let alone a mark.
There are two kinds of egotists: 1) Those who admit it 2) The rest of us
I admit I don't quite know the exact ins and outs of this technology, but a few things do come to mind:
Wouldn't supplying substantial amounts of power through network cable (lets say cat5) make enough EMI to scramble the data going through the other pairs?
Also, would this work in situations using coax cable, where there is no other pair?
Lastly, can you put 120VAC along wires that thin without causing lots of power loss and making a lovely fire hazard?
If you can't see the value in jet powered ants you should turn in your nerd card. - Dunbal (464142)
Here is some info by POE from NYCWireless...
Now just give me wireless repeater base stations powered by tesla coils and I'll be in heaven.
Yup, you'll now have to get a licensed electrician to punch down that patch panel, unless you don't mind fried IT people piling up at the bottom of your 19" rack.
-- Thou hast strayed far from the path of the Avatar.
Golden rule of data cable laying:
Avoid power cables! If you've gotta go near the buggers, cross 'em at right angles.
"Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
So.. we have power over data lines and data over power lines..
:)
What a world, I'm so glad to be alive in 2003
Excuse me, I don't mean to impose, but I am the ocean
An Indian-American Hindu committed to non-violent thought/speech/action alarmed by the global explosion of radical Islam
Ok, so maybe this wasn't exactly what they were talking about. It's still kind of fun though...
The Etherkiller
"The RJ45 connector is a universal outlet," he said. "It's the only one identical in Asia, Europe and the US."
The same is true for FireWire and USB, and those are far more widely available. In fact, USB is increasingly becoming the standard for recharging portable devices, with USB power cables for most PDAs and cell phones available. FireWire might be better for this than USB because it can deliver more power, but maybe the USB standard will catch up.
You can even get a USB toothbrush.
The RJ-45 connectors used with Ethernet really don't do it for me; I think both USB and FireWire connectors are far better designed. I think POE (Power over Ethernet) will remain a niche market.
There have been quite a few posts so far about how running power over data lines is a bad idea and would cause all sorts of bad EMI, killing the data signal. But it actually doesn't. The power going through these is low-voltage DC (I think 12v), *not* high-voltage AC like wall power. AC produces changing magnetic fields which cause EMI, while DC produces a static magnetic field, so the data could care less. This is the same way that USB works (at 5v) and even POTS (plain old telephone systems...those have a full 48V DC...not always very nice when you forget that fact doing wiring). I haven't actually played with any of the equiptment myself, but from what I've read everything is low-voltage and low-power enough not to cause any sorts of problems at all.
Check out the prelimary specs for 802.1u - power over wireless ethernet. They are planning on using microwaves to send the data and power to wireless devices around the home and office.
When information is power, privacy is freedom.
Wouldn't supplying substantial amounts of power through network cable (lets say cat5) make enough EMI to scramble the data going through the other pairs?
If it's DC only and well filtered/buffered, no. If it's RF, or DC that's not well filtered(noise is generated from any kind of switching, even in low power ICs). Buffering it isn't that tough- you can sorta think of it like a bucket under a faucet. As long as your average water needs over time don't exceed the flow out the faucet, you can take whatever you want, even large amounts suddenly, without causing pressure changes in the rest of the house. Now, imagine drawing a cup of water every once in a while from a faucet directly and shutting the water off really hard- helloooo water hammer!(similar things happen when you switch on/off power down a long line, or to/from an inductive component.)
Also, would this work in situations using coax cable, where there is no other pair?
Actually, Dallas Semiconductor(now part of Maxim) came up with what they call the One Wire protocol; it only needs one line for power+data(hence the name, even though you still need some sort of ground.) It's a pretty well set up system, works nicely- plenty of info on the web and their site, and there's even guides on designing a proper network- and shows the effects of cable length on things like pulse smoothing, noise, etc caused by communications and device power draw. It's VERY thorough.
Lastly, can you put 120VAC along wires that thin without causing lots of power loss and making a lovely fire hazard?
Actually, power loss is less with higher voltages- that's why high tension wires are tens of thousands of volts. P = I * V; 100W at 120V is .83 amps, but at 12v, it's 8.3A.
This is important, because the higher the current, the higher the voltage drop; V = I * R. All wire(except superconducting) has some resistance, and the lower the current, the lower the voltage drop end-to-end, and the lower the amount of power(heat) the wire absorbs. Wire(or perhaps more accurately, cable) is rated in terms of maximum voltage mostly from the insulation type(its dielectric strength) and current- its gauge, or thickness of the solid or stranded bundle(larger #'s = smaller thickness).
This is one reason automotive manufacturers want to go to 48V systems; the wiring between the battery and main bus/alternator can be much thinner, for example. Take a look at your battery cables some time- they're VERY heavy gauge. Also, as previously mentioned, stuff like dirt on contacts and corrosion between clamps+terminals or in splices are much less bothersome at lower currents.
Please help metamoderate.
To achieve reasonable distances and power, the voltage will need to be highish.
This reminds me of an incident that happened about 15 years ago. We had an ethernet cable between two buildings. The cable was terminated on computer chassis on each end. Unfortunately the two buildings were powered from different phases, so when I opened a connector I became part of the ground loop passing mains. This was not in USA, but was in a country with real (>200V) power.
Engineering is the art of compromise.
Umm, hello...
Can anyone please tell me what the point of putting real juice down Ethernet would be? Isn't Ethernet like 30 years old? Why don't we come up with a new FireWire/USB type plug with a configurable interface, set it up with +5V, +12V, Ground, Data Send and Data Check, set up generic, open hardware-level frames capable of wrapping all other protocols and a spankin' new cable/plug combo which would shield the voltage lines? I mean, Christ, let's move on. Why are people still talking about Ethernet? Oh, and a better endplug would be nice; one that releases with a sharp jerk, stays put with a slow tug and has a satisfying, soft "click" when engaged.
I realize I will get downmodded for this, but I am being quite serious.