Slashdot Mirror


IP Telephony Drives in Power over Ethernet

GuitarNeophyte writes "The Channel Register states that although the idea for Power Over Ethernet has been around for a long time, the stage may finally be set for it to become an essential factor in our technical lives. One of the main reasons is because of the emergence of ip telephony. 'Telephones need to work in an emergency including when there is a power failure. Traditional telephones do, but IP phones will only do so if there is an uninterrupted power supply (UPS). The only practical way of guaranteeing power supply to a large number of IP phones is PoE.' Will IP telephones bring in PoE?"

22 of 278 comments (clear)

  1. No 911? Quote the VOIP reseller... by TimTheFoolMan · · Score: 5, Funny

    ...nevermore... nevermore....

    Tim

    1. Re:No 911? Quote the VOIP reseller... by TimTheFoolMan · · Score: 3, Insightful

      Troll?

      I guess I should have writte POE in big, bold letters to make sure everyone got the joke.

      Tim

  2. Ethernet over Power? by GreatRedShark · · Score: 5, Funny

    Apparently, my cousin has Ethernet over Power, that was installed by The Internet Service Guy...

    It would be interesting to see what happens if you ran Ethernet over Power on a system powered by Power over Ethernet... who would win? an epic battle, to be sure! ...or maybe they would cancel each other out, and you'd just get regular ethernet? ...or maybe it would be like a divide-by-zero, and your NIC would explode? :P

    1. Re:Ethernet over Power? by FleaPlus · · Score: 3, Funny

      Apparently, my cousin has Ethernet over Power, that was installed by The Internet Service Guy...

      Does the cord for it look something like this?

      http://www.fiftythree.org/etherkiller/

    2. Re:Ethernet over Power? by Ray+Radlein · · Score: 4, Funny

      If you could somehow combine the two, you might, at long last, realize the ancient dream of Power-over-Powerlines! Then we can return to tackling the thorny problem of delivering Ether via Ethernet.

  3. Useful by Arghdee · · Score: 3, Insightful

    That'll be great when there's a storm, and trees bring down the power lines.

  4. Re:UPS in the Switch... by 19thNervousBreakdown · · Score: 3, Funny

    Or you could just plug the switch into a UPS...

    Smoke much?

    --
    <xml><I><am><so><damn>Web 2.0</damn></so></am></I></xml>
  5. This does not necessarily follow. by MindNumbingOblivion · · Score: 5, Interesting
    If we lived in a world without cell phones, I would say that yes, this would be a likely outcome. However, I live in a college town, where I'd say 9/10 people have a cell phone as their primary means of telecommunication. The attitude toward a land line is that it's for old people and businesses.

    I'd say that we will eventually have PoE, but I don't think it will be a necessary consequence of VoIP or telephony. I have VoIP, but I use it exclusively for the three hours a day I work as a call desk support monkey for my company. If I had an emergency, I have my cell phone on me as well.

    This is something I've wondered about a lot: how many slashdotters out there use VoIP as their primary telecommunications resource? How many would use telephony once x gets improved?

    --
    #define CLUE 0
  6. Deeper Implications by Comatose51 · · Score: 4, Insightful

    I remember a while back there was an article on Slashdot about how PoE can become an universal power standard. While there are different plugs and voltages used around the world, PoE has a standard jack. Sure PoE is low powered but with miniaturization, many of our devices can be powered off of PoE. With VoIP driving the spread of PoE, I hope this will build momentum in making the prediction come true. Imagine going to another country and needing to bring just a CAT 5 cable instead of a power adapter.

    --
    EvilCON - Made Famous by /.
  7. Better Solution by dracocat · · Score: 4, Interesting

    We were facing the same problem and found it cheaper to inject POE right at the phone untill we found that you could buy a 24 port power injector for a couple hundred dollars off of ebay. Put these things next to your switch and inject it there.

    Something is wrong with the math currently because a 24 port switch with POE is almost three times as expensive than a 24 port switch & a 24 port POE injector.

    1. Re:Better Solution by RicoX9 · · Score: 3, Informative

      Nice thing about PoE in the switch is that you have the ability to remotely power cycle a device.

      I have 135 wireless access points and 100+ IP telephones in this hospital. If one freaks out and becomes non-responsive, I can shut the port down and bring it back up for a cold start. Doesn't happen very often, but I live 45 miles away, and it's a lifesaver in the middle of the night.

      Also, the switch will auto-detect whether the device needs power or not. The injector panels I've seen are dumb, and will happily provide enough juice to fry your NIC if you happen to plug into the wrong jack.

  8. Re:Make little sense... by BigDog1942 · · Score: 3, Insightful

    Yeah, I've had a wireless phone for years, never a single problem during a blackout, it works fine. So tell me again why we need to reinvent the cell phone?

  9. Re:Wireless? by grozzie2 · · Score: 3, Funny
    For that we need to advance to power over wireless. It's not as big a step as most seem to think. Typical notebook has a 19V supply capable of 2.5 amps, and it's not fully used, so for round figures, lets call that 40 watts. Assuming you get a 25% efficiency in the conversion at the reciever, and you want to power 4 devices off a single access point, you will need 4*4*40=640 watts at 2.4 ghz. Those transmitters are already in mass production, currently in use for microwave ovens, so it's not even a large engineering or manufacturing challenge to get units in mass quantity. The only real issue is designing the reciever.

    But, one other detail, there will probably need to be a warning on the box, for use only by folks that have already HAD thier children.

  10. internet vs phone line by airjrdn · · Score: 3, Informative

    My phone line has rarely gone down if ever. I can't come close to saying that about my internet connections, cable or DSL. The fact that we have two small children means when I pick up that phone in an emergency, I want it to work. I don't want to be mucking around rebooting computers and routers. That's why I've stayed away from VOIP over my existing internet connection.

    Any thoughts on the reliability of this? Will VOIP ever be as solid as good old copper? I mean, you have issues (DDOS) with VOIP you just don't have with traditional PSTN service.

    1. Re:internet vs phone line by kitzilla · · Score: 5, Insightful
      > My phone line has rarely gone down if ever. I can't come close to saying that about my internet connections, cable or DSL. The fact that we have two small children means when I pick up that phone in an emergency, I want it to work.

      No freaking kidding. The phones were about the only thing that survived Hurricane Ivan last September (in my neighborhood, at least). When Hurricane Dennis went through last week, we were once again power/cable/waterless, but the phone still worked.

      So I fired up my generator, jacked the laptop into Earthlink dial-up, and was right back online.

      I'm in no hurry at all to abandon traditional telephony. It works.

      --
      This is my post. There are many others like it. If you don't like what you read here, go try one of the others.
  11. Re:Make little sense... by sbraab · · Score: 3, Insightful

    and what do you think will power those access points? oh right POE

  12. Power from a wall outlet ... how exciting by nicodaemos · · Score: 3, Funny

    Bah, I can't wait for POWF - Power Over WiFi. Now that would be pretty darn cool!

  13. Traditional telephones do? by slashdot.org · · Score: 4, Insightful

    Telephones need to work in an emergency including when there is a power failure. Traditional telephones do

    The majority of phones today are cordless and practically none work without power.

    I used to buy cordless phones that had a speaker on the base unit for this very reason, but alas, those also don't work anymore without power, on most modern phones.

  14. Re:I think it will... by afidel · · Score: 3, Insightful

    WTF are you talking about? PoE as ratified by the IETF does a low voltage chat over the unused pairs to determine if the device needs power, the likelyhood of a device not needing power and randomly responding over the unused pair correctly to trigger power is essentially nill. Certain pre-standard PoE injectors (such as those shipped with certain Cisco/Aironet AP's) may cause damage when used on a port with other equipment attached, but anything which is compliant with the 802.3af standard should have an essentially zero percent chance of frying attached equipment.

    --
    There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
  15. Not just Phones by jonbrewer · · Score: 4, Informative

    PoE (802.3af) is incredibly useful in for business deployments of video cameras and wifi access points, not to mention mini-switches and outdoor wireless bridge equipment. You can even power a laser link with PoE. It makes life easier for those averse to paying out huge amounts of cash to have an electrician come in and put in new outlets. I've been playing with PoE splitters recently to power non PoE gear at 5 & 12V DC - the splitters are $35 ea and are switchable between voltages.

  16. Re:I think it will... by robfoo · · Score: 3, Funny

    I use this for my Power-over-Ethernet needs :)

    I'm not sure what standards it supports, but it's cheap to manufacture!

  17. Re:Make little sense... by skids · · Score: 4, Interesting

    Yeah, there are solar cell price drops on the horizon. Well I guess it depends on what you define as the horizon. There's now a room-temperature nano-self-assembly spray that turns itself into solar cells in the lab. Made, I might add, by the co-author (Warner) of "green chemistry" who is into all sorts of really cool stuff and worth keeping track of. Saw him speak a while back and he was very entertaining.

    PoE rocks though. As an EE, I read the spec expecting to be horrified at all the shortcuts, brainfarts, and other cruft you find in other standards associated with ethernet or "lets-jam-everything-over-frame-based-networks-whe re-it-dont-belong." But the standard was surprisingly thorough, and I very much look forward to a wider range of PoE products becoming available 1) because they will make it easy to power from renewable sources (48-56V DC, no 120V 60HZ invertor needed) and 2) because I really hate USB and it would be nice if PoE took a shot at it's market niche.