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New Computer Powered By PoE
BlakeCaldwell writes "BBC News is reporting about a new PC that's powered via a network cable rather than through a wall socket. The computer only requires 12 watts, lower than the upper limit of 15.4 watts that power over ethernet (PoE) can supply. FTA: 'PoE could end up being a universal power supply system as the cables and connectors for it are the same all over the world. By contrast power sockets and plugs differ by country.'"
Slashdot has discussed "Power over Ethernet: IEEE 802.3af" and how the Apple AirPort Base Station supports POE. There also appears to be a website dedicated to Power over Ethernet. Ummmmm ... maybe I could use POE to power my christmas lights ... although I'd need a bit more than 15 Watts! ;-)
The Power over ethernet website which has links to articles and products (check the dates on some of the articles).
A good article about ins and outs of PoE
Don't confuse PoE with Perl Object Environment or Poe Puzzle
Nevertheless it is a good concept with lot of benefits (as well as drawbacks)
Cost savings. PoE significantly reduces the need for electricians to install conduit, electrical wiring, and outlets throughout the facility. In larger installations, these items can be relatively expensive. Consider an installation of 50 or more access points. This requires lots of conduits, outlet boxes, electrical wiring and the time of a qualified electrician. The low costs of deploying PoE compared to traditional electrical circuits leads to worthwhile returns on investment.
Flexible access point locations. With PoE, a wireless LAN designer has greater freedom to locate access points. You don't need to depend on only locations within short distances from AC outlets. The independence from AC outlets also makes it easier to relocate access points in the future if needed to fine-tune RF coverage or increase capacity. Thus, PoE enables companies to more easily maximize the performance of a wireless LAN.
Higher reliability. Systems with fewer wires tend to be more reliable. With WLANs not using PoE, cleaning people may unplug an access point to use its AC outlet to power vacuum and buffing equipment. Electricians rewiring electrical circuits could inadvertently cut power to an access point. PoE eliminates the possibility of situations that disrupt the operation of the network.
Enhanced operational support. Many PoE devices implement SNMP (simple network management protocol), which enables support staff to remotely manage the electrical power supplied to the access points. For example, support staff can disable a PoE-enabled access point by shutting off its power after detecting a breach of security. The temporary disabling of the access point can protect against an intruder from continuing unauthorized access to corporate systems. Other SNMP-based features enable the monitoring of the condition and consumption of power, which enhances the ability to ensure smooth and efficient network operations.
Simpler international development. For manufacturers, PoE offers the benefit of the vendor not needing to provide different power cords for various countries. This not only helps keep the cost of access points done -- it's one less piece of equipment that installers need to worry about
POE wasnt really designed for everyday use, it was designed for manufacturers to have an easy way to power small devices on their control network. Seeing as many control networks are now going to ethernet rather than serial communcattions (DH+, Modbus+, etc). This allows them to remove a lot of the extra cabling from their orginal networks.
Also POE is used in a lot of place s to power the wireless APs for WiFi.
The ethernet port *is* the power input. RJ-45s have 8 connectors. PoE uses some of the spare conductors to provide power, the rest still do data.
ObRTFA:
Power-over-Ethernet (PoE) works because when data is sent down network cables it is represented by voltages. PoE uses spare wires in cables that link computers back to network hubs and pump power down these, separate from data traffic.
Random and weird software I've written.
No. Gigabit ethernet uses the same pairs as 10/100 ethernet.
No. 1000Base-T (802.3ab), or Gigabit Ethernet, does indeed require all four pairs (8 conductors) of the cable.
Actually, it works by put 40VDC between the TX and RX pairs. The coupling transformers block the DC before it gets to the PHY. It is compatible with gigabit. POE allows the use of the unused lines. This is needed for a seperate power injector, which can't touch the signal lines.
A cable modem that doesn't support PoE draws about 20 watts from the wall.
Network equipment that adheres to the PoE spec has to draw enough power from the wall to power itself and the devices on each of its ports.
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12V is no longer standard for cars
Were that I say, pancakes?
The only thing I could fond on their site POET. Apparently stands for Power Over Ethernet Touchscreen.
Were that I say, pancakes?
(Using conservative figures)
At 100 watts, a monitor consumes 1200 watts in 12 hours or (at 7 cents per kWh) about $.084 in electricity every night. Call it $25/year.
1000 monitors waste $25,000/year.
Depending on your climate, heat dissipation is really hard to figure, since in the winter all those monitors made the buildings easier to heat in the winter, harder to cool in the summer. Not very efficient, but it's there.
I don't know what effect power cycling a monitor has on its longevity, but I bet doing it once a day for twelve hours would increase useful life, not decrease it on average.
sigs, as if you care.
"By contrast power sockets and plugs differ by country."
Wrong wrong wrongedy wrong.
Yes, different countries use different mains sockets, and they use different voltages / frequencies.
However, nearly every computer built in the last 10 years has a multivoltage / multifrequency power supply, and they always have the standard IEC socket.
When building a rack system, computers are connected to special power strips that have IEC sockets. Regardless of country, the cabling stays the same.
With Active-PFC power supplies, the voltage selection is automatic. Most notebook power supplies have automatic voltage selection as well. Heck, even my cellphone can run on 220V/50Hz.
Honestly, the best solution for users that don't need that much horsepower is to switch to thin clients. With the thin clients, power consumption is easily under 12 watts per desktop, users can be centrally managed, and desktop horsepower can be upgraded in a single system replacement.
I used to admin a Citrix network, and I have to say that the idea makes a lot of sense. Most of the issues with the setup stemmed from the fact that we were on NT 3.51 and not from the fact that our users were on a shared system. Users *still* ran their little "bouncing sheep" and "frog in a blender" type of programs (not a good thing, but necessary to allow the users to be "happy" with their system), and we saved money on hardware, support costs, and power usage. Can't get much better than that!
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PoE can use either the extra leads, or can impress power by placing a DC potential between the standards TX and RX pairs, which is then recovered by the powered device by using a center tap on each of the RX and TX transformers.
So you CAN run PoE on GigE.
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