Inline power options for VOIP phones

Discussion in 'VOIP' started by hal@nospam.com, Oct 20, 2004.

  1. Guest

    Has anyone taken a close look at cost comparisons between using inline
    powered switches vs. UPS power backup at the client station? It is
    cost effective to use inline power? Per port costs seem to be close
    to 3X with Cisco modules. Are there stand alone units installed
    inline between the switch and client device that provide power or is
    the present only option to use powered switches or switch modules? I
    had heard that if using Cisco powered modules and non-Cisco phones you
    need a converter dongle. Is that still true?

    thanks

    Hal
    , Oct 20, 2004
    #1
    1. Advertising

  2. Dmitri Guest

    wrote:




    > Has anyone taken a close look at cost comparisons between using inline
    > powered switches vs. UPS power backup at the client station? It is
    > cost effective to use inline power? Per port costs seem to be close
    > to 3X with Cisco modules. Are there stand alone units installed
    > inline between the switch and client device that provide power or is
    > the present only option to use powered switches or switch modules? I
    > had heard that if using Cisco powered modules and non-Cisco phones you
    > need a converter dongle. Is that still true?


    > thanks


    > Hal


    You can buy a device designed specifically to sit between your regular,
    non IEEE 802.2af - compliant switch and supply power to a 802.3af -
    compliant terminal device, such as VoIP phone. They are called mid-span
    power supplies. PowerDsine makes those (as well as other people) and sells
    under OEM to lots of other (bigger name) manufacturers. They come in
    different port quantities between 1 and 24.

    As far as costs are concerned, it has been a conventional wisdom that it
    is cheaper to have a UPS-protected mid-span power supply to send the
    inline power to the phones than to have a UPS installed at every phone
    location (and much more elegant if you ask me). However, with the prices
    of low-end UPSes falling, I'm not sure the common wisdom would survive
    scrutiny if someone was actually to look at the price difference. Besides,
    distributed UPSes help to get rid of the single point of failure problem.
    Anyways, I can buy a 350VA UPS that would power a VoIP phone for as much
    as 45 minutes to an hour for $35, and every IEEE 802.3af port (midspan or
    switch upgrade) costs on the order of $50. So, customer's convenience
    aside, I think remote UPSes may be a cheaper solution, and less prone to
    failure.

    --
    Dmitri Abaimov, RCDD
    http://www.cabling-design.com
    Cabling Forum, color codes, pinouts and other useful resources for
    premises cabling users and pros
    http://www.cabling-design.com/homecabling
    Residential Cabling Guide
    -------------------------------------




    ##-----------------------------------------------#
    Article posted with Cabling-Design.com Newsgroup Archiv
    http://www.cabling-design.com/forum
    no-spam read and post WWW interface to your favorite newsgroup -
    comp.dcom.voice-over-ip - 12188 messages and counting
    ##-----------------------------------------------##
    Dmitri, Oct 20, 2004
    #2
    1. Advertising

  3. papi Guest

    On Wed, 20 Oct 2004 12:59:21 -0600, hal wrote:

    > Has anyone taken a close look at cost comparisons between using inline
    > powered switches vs. UPS power backup at the client station? It is
    > cost effective to use inline power? Per port costs seem to be close
    > to 3X with Cisco modules. Are there stand alone units installed
    > inline between the switch and client device that provide power or is
    > the present only option to use powered switches or switch modules? I
    > had heard that if using Cisco powered modules and non-Cisco phones you
    > need a converter dongle. Is that still true?
    >
    > thanks
    >
    > Hal


    My company has just recently decided to go with Panduit's powered patch
    panels - great way of keeping non-PoE still network capable gear around -
    as these guys' stuff plays well with Cisco's legacy, as well as 802.3af
    new PoE stds.

    HTH,
    Papi
    papi, Oct 22, 2004
    #3
  4. stephen Guest

    "Dmitri(Cabling-Design.com)" <> wrote
    in message news:1098301727.fSJZz8nB2WCq4rkWQYzNiQ@bubbanews...
    > wrote:
    >
    >
    >
    >
    > > Has anyone taken a close look at cost comparisons between using inline
    > > powered switches vs. UPS power backup at the client station? It is
    > > cost effective to use inline power? Per port costs seem to be close
    > > to 3X with Cisco modules.


    Depends on what you compare - chassis blades are a small uplift (most of the
    recent ones use a daughtercard on a non 802.3af module), but inline power is
    not available on the cheaper cisco stackable switches, so that could affect
    the relative cost.

    Are there stand alone units installed
    > > inline between the switch and client device that provide power or is
    > > the present only option to use powered switches or switch modules? I
    > > had heard that if using Cisco powered modules and non-Cisco phones you
    > > need a converter dongle. Is that still true?


    ignoring exactly which inline power system you use - you will still need a
    UPS on the ethernet switch and other central kit.

    Cisco are starting to support 802.3af on their kit - but i am not sure if
    any of the phones have migrated yet - you need to check the spec.
    >
    > > thanks

    >
    > > Hal

    >
    > You can buy a device designed specifically to sit between your regular,
    > non IEEE 802.2af - compliant switch and supply power to a 802.3af -
    > compliant terminal device, such as VoIP phone. They are called mid-span
    > power supplies. PowerDsine makes those (as well as other people) and sells
    > under OEM to lots of other (bigger name) manufacturers. They come in
    > different port quantities between 1 and 24.


    last time i checked power dsine costs - a patch panel was about the same as
    buying a cisco inline power switch with the same number of ports. given that
    it sounds like you have to buy the switch anyway.....

    an inline power switch is simpler since you avoid the wiring complications
    for the in span system,

    > As far as costs are concerned, it has been a conventional wisdom that it
    > is cheaper to have a UPS-protected mid-span power supply to send the
    > inline power to the phones than to have a UPS installed at every phone
    > location (and much more elegant if you ask me). However, with the prices
    > of low-end UPSes falling, I'm not sure the common wisdom would survive
    > scrutiny if someone was actually to look at the price difference. Besides,
    > distributed UPSes help to get rid of the single point of failure problem.


    standard practice is use a dual power switch, and use UPS on 1 feed, so loss
    of UPS doesnt kill the switch.

    this tends to push you onto chassis switches with the cisco range (none of
    the stackables comes with dual power - you use an external dual feed power
    system) - Catalyst 4500s is the common choice for a chassis switch for a
    wiring closet.

    > Anyways, I can buy a 350VA UPS that would power a VoIP phone for as much
    > as 45 minutes to an hour for $35, and every IEEE 802.3af port (midspan or
    > switch upgrade) costs on the order of $50. So, customer's convenience
    > aside, I think remote UPSes may be a cheaper solution, and less prone to
    > failure.
    >
    > --
    > Dmitri Abaimov, RCDD
    > http://www.cabling-design.com
    > Cabling Forum, color codes, pinouts and other useful resources for
    > premises cabling users and pros
    > http://www.cabling-design.com/homecabling
    > Residential Cabling Guide
    > -------------------------------------
    >
    >
    >
    >
    >
    > ##-----------------------------------------------##
    > Article posted with Cabling-Design.com Newsgroup Archive
    > http://www.cabling-design.com/forums
    > no-spam read and post WWW interface to your favorite newsgroup -
    > comp.dcom.voice-over-ip - 12188 messages and counting!
    > ##-----------------------------------------------##

    --
    Regards

    Stephen Hope - return address needs fewer xxs
    stephen, Oct 24, 2004
    #4
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Bill F
    Replies:
    2
    Views:
    406
  2. Bernie
    Replies:
    3
    Views:
    7,407
    Jerry
    Feb 14, 2004
  3. joseph
    Replies:
    3
    Views:
    1,225
  4. Giuen
    Replies:
    0
    Views:
    668
    Giuen
    Sep 12, 2008
  5. Neddy
    Replies:
    5
    Views:
    5,034
    waltjones40
    May 27, 2011
Loading...

Share This Page