Power Over Ethernet

Discussions of the Ethernet/IEEE 802.3 protocols.

Power Over Ethernet

Postby razor » Thu Dec 15, 2005 4:20 am

Hi guys, im just new in this forum. Im looking info about Power Ove
Ethernet. It would be great if someone will give me a link for this
I wanted to know . . .

1. What's with this technology?
2. Will this boom in the market
3. Pros and cons

Such things like that. . .

Thank you
razor
 

Re: Power Over Ethernet

Postby Tomi Holger Engdahl » Thu Dec 15, 2005 4:20 am

blackphnx@gmail-dot-com.no-spam.invalid (razor) writes:

Hi guys, im just new in this forum. Im looking info about Power Over
Ethernet. It would be great if someone will give me a link for this.
I wanted to know . . .

1. What's with this technology?

Nowadays standardized and starts to be pretty widely supported by devices.

Proprietary implementations that were used earler are going out.

2. Will this boom in the market?

I don't know. Maybe at least some small boom.

3. Pros and cons.

Pros:
Can supply power though same wiring as Ethernet signal to
power devices like IP phones, WLAN access points etc..
Less wiring needed for those devices (just net cable),
possibly for easier power backup systems (PoE powered WLAN
stations receiver power from one point from switch, just put
UPS/generator there and you whole wireless network infrastructure
does not stop if mains power goes out).

Cons:
Switches that can supply power tend to be quite expansive.


More information on power over ethernet system can be found at
http://www.epanorama.net/links/tele_lan.html#poe

--
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at
http://www.epanorama.net/
Tomi Holger Engdahl
 

Re: Power Over Ethernet

Postby William P.N. Smith » Thu Dec 15, 2005 12:20 pm

blackphnx@gmail-dot-com.no-spam.invalid (razor) wrote:

Hi guys, im just new in this forum. Im looking info about Power Over
Ethernet. It would be great if someone will give me a link for this.

I'd start with http://poweroverethernet.com/ and Google.

It's an interesting technology, but still in it's infancy, and
suffering from the chicken/egg problem. I've started to deploy it in
limited ways for some of my clients, and it does what it's supposed
to.

Since it's still early, you have to be wareful of products claiming
802.3af when they aren't (Linksys WAPPOE devices, for instance, apply
power to the spare pairs without bothering to check if there's a valid
client on the other end).

Prices tend to be obscenely high, though the PhiHong stuff is on the
order of $25 for the single-port midspan.

Finding client devices with PoE already in them isn't easy, life will
be so much better when the client hardware is cheap enough that it's
installed as a matter of course in all but the lowest-end devices.

I haven't gotten to the point where I'm buying products specifically
for their PoE capabilities...
William P.N. Smith
 

Re: Power Over Ethernet

Postby stephen » Fri Dec 16, 2005 12:06 am

"William P.N. Smith" <news05@compusmiths.com> wrote in message
news:m7q2q1t3q608b10l2fip79g7hshj593n0a@4ax.com...
blackphnx@gmail-dot-com.no-spam.invalid (razor) wrote:

Hi guys, im just new in this forum. Im looking info about Power Over
Ethernet. It would be great if someone will give me a link for this.

I'd start with http://poweroverethernet.com/ and Google.

It's an interesting technology, but still in it's infancy, and
suffering from the chicken/egg problem. I've started to deploy it in
limited ways for some of my clients, and it does what it's supposed
to.

Since it's still early, you have to be wareful of products claiming
802.3af when they aren't (Linksys WAPPOE devices, for instance, apply
power to the spare pairs without bothering to check if there's a valid
client on the other end).

Prices tend to be obscenely high, though the PhiHong stuff is on the
order of $25 for the single-port midspan.

Finding client devices with PoE already in them isn't easy, life will
be so much better when the client hardware is cheap enough that it's
installed as a matter of course in all but the lowest-end devices.

certain classes of device seem to all have PoE - IP phones spring to mind,
and as mentioned above a lot of commercial access points for 802.11.

the standard limits the power to 13.x W for the device (the switch might
have to send 15W due to cable losses).

The power rating is not enough for a lot of otherwise useful ideas, such as
charging + running a laptop. Be nice to have it on a PDA though.....

1 big problem is the aggregate power in a big switch - one of the high end
ciscos is going to have 9 kW power supplies soon........
I haven't gotten to the point where I'm buying products specifically
for their PoE capabilities...

someone did make a PoE electric toothbrush for a show......

--
Regards

stephen_hope@xyzworld.com - replace xyz with ntl
stephen
 

Re: Power Over Ethernet

Postby William P.N. Smith » Fri Dec 16, 2005 2:08 am

"stephen" <stephen_hope@xyzworld.com> wrote:
someone did make a PoE electric toothbrush for a show......

Yeah, there are some apps that look really neat, like that PoE clock
that sets itself using SNTP, but it really should cost less than a
computer that does the same thing. 8*)
William P.N. Smith
 

re:Power Over Ethernet

Postby razor » Fri Dec 16, 2005 4:20 am

thanks guys for all the info. i'll share this with my classmates an
it will be a great help for our research. :

you guys rulesz! 8
razor
 


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