+ Post New Thread
Page 1 of 2 12 LastLast
Results 1 to 15 of 22
General Chat Thread, Power over ethernet in General; Does anyone know if there is a PoE based TFT out there? I know you can get Think Clients that ...
  1. #1
    wesleyw's Avatar
    Join Date
    Dec 2005
    Location
    Kingswinford
    Posts
    2,205
    Thank Post
    223
    Thanked 50 Times in 44 Posts
    Blog Entries
    1
    Rep Power
    30

    Power over ethernet

    Does anyone know if there is a PoE based TFT out there? I know you can get Think Clients that are but I was wondering about screens?


    Wes

  2. #2
    gwendes's Avatar
    Join Date
    Jan 2007
    Location
    London
    Posts
    1,495
    Thank Post
    161
    Thanked 30 Times in 29 Posts
    Rep Power
    26

    Re: Power over ethernet

    ooooo...
    You could probably inject the monitor's PSU over ethernet and then collect it the other end.
    Would be cool if you could get VGA too - poor little cat5!
    Love the idea - what are you gonna do with it?

  3. #3
    wesleyw's Avatar
    Join Date
    Dec 2005
    Location
    Kingswinford
    Posts
    2,205
    Thank Post
    223
    Thanked 50 Times in 44 Posts
    Blog Entries
    1
    Rep Power
    30

    Re: Power over ethernet

    Well I was thinking of installing around 50 points per room and setting up Thin Clients and TFTs to gain power and data but I haven't been able to find anything for TFTs some thin clients only use about 4w but TFTs are more like 30w so I'm not sure if it's possible or not?


    Wes

  4. #4

    Join Date
    Aug 2005
    Location
    London
    Posts
    3,154
    Thank Post
    114
    Thanked 527 Times in 450 Posts
    Blog Entries
    2
    Rep Power
    123

    Re: Power over ethernet

    As far as I know, you can't do what you want at the moment but I've read about various attempts to change the PoE standard to allow enough power down the cable to power something like a laptop.

    Not sure if this would give you enough for a TFT - I'm guessing that the idea is to get enough current to charge the battery slowly rather than to power the whole machine but all sorts of things are possible :-)

  5. #5

    Geoff's Avatar
    Join Date
    Jun 2005
    Location
    Fylde, Lancs, UK.
    Posts
    11,803
    Thank Post
    110
    Thanked 583 Times in 504 Posts
    Blog Entries
    1
    Rep Power
    224

    Re: Power over ethernet

    The Specs for PoE limit the wattage for each port to 12.95W, this is insufficient to run a TFT.

    http://en.wikipedia.org/wiki/Power_o...vels_available

  6. #6
    gwendes's Avatar
    Join Date
    Jan 2007
    Location
    London
    Posts
    1,495
    Thank Post
    161
    Thanked 30 Times in 29 Posts
    Rep Power
    26

    Re: Power over ethernet

    Here's a 12W TFT

    http://www.sharp-world.com/corporate.../tj1/pdf/6.pdf

    and that's old (1997)

    Theoretically possible but never been done ASAIK

  7. #7

    plexer's Avatar
    Join Date
    Dec 2005
    Location
    Norfolk
    Posts
    13,343
    Thank Post
    624
    Thanked 1,584 Times in 1,421 Posts
    Rep Power
    414

    Re: Power over ethernet

    The notes section at the bottom of that wikipedia article is the most interestnig.

    Using 2 pairs for + and 2 pairs for - you could provide is 72W taking into account voltage drop on a 100m cable you could provide 59W.

    So it would be possible to run 2 cat5's for each machine poe + data for the thin client from one and power from the other.

    Ben

  8. #8
    wesleyw's Avatar
    Join Date
    Dec 2005
    Location
    Kingswinford
    Posts
    2,205
    Thank Post
    223
    Thanked 50 Times in 44 Posts
    Blog Entries
    1
    Rep Power
    30

    Re: Power over ethernet

    What sort of a fire risk would it be though? I can just imagine 10 rooms turn on in the morning for instance and the fire brigade are out five minutes later





    Wes

  9. #9

    plexer's Avatar
    Join Date
    Dec 2005
    Location
    Norfolk
    Posts
    13,343
    Thank Post
    624
    Thanked 1,584 Times in 1,421 Posts
    Rep Power
    414

    Re: Power over ethernet

    There isn't one if you look at the spec that's what the cable is rated for it won't melt and burn.

    If you were to use 1 conductor for + and 1 conductor for - and try and run that then it will melt.

    Would you like me to test it with a 100m of cat5?

    Ben

  10. #10

    Ric_'s Avatar
    Join Date
    Jun 2005
    Location
    London
    Posts
    7,590
    Thank Post
    109
    Thanked 762 Times in 593 Posts
    Rep Power
    180

    Re: Power over ethernet

    Just looking at this from a different angle... couldn't you just buy extra big dado and stick the PSUs inside? I have done this with some projector installs for the Nuvo speaker amp (it looks very tidy).

  11. #11
    wesleyw's Avatar
    Join Date
    Dec 2005
    Location
    Kingswinford
    Posts
    2,205
    Thank Post
    223
    Thanked 50 Times in 44 Posts
    Blog Entries
    1
    Rep Power
    30

    Re: Power over ethernet

    @ Ric_: I was thinking it would be a cheaper and simpler solution than putting in 25 network points and 25 power points?

    @Plexer: If you wouldn't mind testing it and letting me know the results that would be fantastic!

    Wes

  12. #12
    enjay's Avatar
    Join Date
    Apr 2007
    Location
    Reading, Berkshire, UK
    Posts
    4,485
    Thank Post
    282
    Thanked 196 Times in 167 Posts
    Rep Power
    75

    Re: Power over ethernet

    Quote Originally Posted by srochford
    allow enough power down the cable to power something like a laptop. Not sure if this would give you enough for a TFT
    Not sure what sort of kit you have, but our laptops pull much more juice than the TFTs (heck, my laptop on standby is about the same as my TFT in full swing).

    Quote Originally Posted by srochford
    I'm guessing that the idea is to get enough current to charge the battery slowly rather than to power the whole machine but all sorts of things are possible :-)
    That can't be - if it was sufficient only to charge the battery not actually run the laptop, then it would eventually turn off, as power out would be greater than power in...

  13. #13

    Ric_'s Avatar
    Join Date
    Jun 2005
    Location
    London
    Posts
    7,590
    Thank Post
    109
    Thanked 762 Times in 593 Posts
    Rep Power
    180

    Re: Power over ethernet

    @wesleyw: You would be surprised how little of the cost of putting in dado trunking and power is actually the power. Compare this cost to PoE injectors (approx. £20 each) and the power receiver (don't know how much one of those might be but assume £10)... that's a conservative cost of £750 just for the equivalent of 25 single sockets.

  14. #14
    enjay's Avatar
    Join Date
    Apr 2007
    Location
    Reading, Berkshire, UK
    Posts
    4,485
    Thank Post
    282
    Thanked 196 Times in 167 Posts
    Rep Power
    75

    Re: Power over ethernet

    Quote Originally Posted by Ric_
    that's a conservative cost of £750 just for the equivalent of 25 single sockets.
    Which compares quite nicely against one price I saw for electrical work which was £50 per socket (£1250 for 25).

  15. #15

    plexer's Avatar
    Join Date
    Dec 2005
    Location
    Norfolk
    Posts
    13,343
    Thank Post
    624
    Thanked 1,584 Times in 1,421 Posts
    Rep Power
    414

    Re: Power over ethernet

    Poe injector £11 for 3 com ones, plus you need to have 25 sockets at the injecting end to plug them into cascading and multiple trailing leads not recommended so if you've got to put power in you may as well put it in at the desktop.

    Ben

SHARE:
+ Post New Thread
Page 1 of 2 12 LastLast

Similar Threads

  1. Ethernet Splitter
    By istanlfc in forum Hardware
    Replies: 21
    Last Post: 3rd September 2009, 08:58 PM
  2. VGA over Ethernet Question
    By mitchell1981 in forum Hardware
    Replies: 13
    Last Post: 2nd November 2007, 07:31 PM
  3. Power Over Ethernet
    By timbo343 in forum Wireless Networks
    Replies: 9
    Last Post: 20th May 2007, 08:58 PM
  4. Ethernet splitters
    By _Bat_ in forum Hardware
    Replies: 28
    Last Post: 4th May 2007, 06:54 PM
  5. POE Power over Ethernet for wireless
    By u8dmtm in forum Wireless Networks
    Replies: 15
    Last Post: 7th May 2006, 03:19 PM

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •