Dmitri(Cabling-Design.com
Guest
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 Posted:
Wed Oct 20, 2004 11:48 pm Post subject:
Re: Inline power options for VOIP phones |
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hal@nospam.com wrote:
| Quote: | 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
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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
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papi
Guest
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| Posted:
Fri Oct 22, 2004 4:28 am Post subject:
Re: Inline power options for VOIP phones |
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On Wed, 20 Oct 2004 12:59:21 -0600, hal wrote:
| Quote: | 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
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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 |
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