[Asterisk-Users] Asterisk & POE

[SCollins]

What PoE Switch are you thinking of using or own?  The 802.3af Spec, as I  
understand it, uses a special Fast Link Pulse to detect if the Powered  
Device needs to receive power.

However, there are vendors that have pre-spec (before 2003) Switches that  
MAY NOT follow the spec.

There are also (2) differant types of PoE Sourcing Switches.

End-Span and Mid-Span

Mid-Span sits between the IP phone that needs powers and the Data Switch  
that connects to the network.  The Mid-Span ONLY supplies power to the IP  
Phone and thus requires the addition of an Ethernet Sitch or Hub to  
provide the connectivity to the network.

End-Span devices incorporate the Power Sourcing capabilities of the  
mid-Span and the Ethernet connectivity of a Switch.

Now it gets tricky.  As I understand the spec, and from my own experience,  
a PoE Switch can source power over pins 1,2,3, and 6 as well as Ethernet  
connectivity OR it can source PoE over the unused pins 4,5,7 and 8 BUT it  
does not have to do both.

On the other hand, a 802.3af compliant PoE device (IP phone, Wireless AP,  
Surveilance Camera)must be able to detect the FLPs on either of the (4)  
pairs and then source according to what the PoE Switch is sending.

Yes, a PoE Switch can toast a NIC/PCMCIA card if the PoE Switch is a  
Mid-Span device or power Injector (I don't believe these device are  
capable of detecting the capabilities of a Powered Device and thus they  
just source power down the designated Rx pairs - someone correct me if I'm  
wrong).

I would look at the product Data Sheet for your phone and find out how it  
handles sourced power and if it's 802.3af IEEE spec compliant.

Look at the PoE Swtich options Cisco, 3Com, Netgear, Asante, HP etc. I  
know from experience that Cisco is a great solution if you have a big  
budget for a Cat 3550.  3Com is Spec compliant and provides Power over  
pins 1,2,3 and 6 ONLY. Netgear is the least expensive solution, but with  
my experience it's hard to get support if you have problems with their  
product, unless you purchase a Service Contract (warranty support only  
entitles you to speak to 1st level Tech who can answer basic questions)

Hope some of this helped.

Sean





   tOn Tue, 19 Apr 2005 17:32:00 +1000, Paul Hales <paulh at adairs.com.au>  
wrote:

> Snom 200's & Polycom 600's.
>
> Polycom 500's with the special lead.
>
> Later,
>
> PaulH
>
> -----Original Message-----
> From: Kristof Hardy [mailto:kristof.hardy at catsanddogs.com]
> Sent: Tuesday, 19 April 2005 5:05 PM
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Cc: paulh at adairs.com.au
> Subject: Re: [Asterisk-Users] Asterisk & POE
>
> Paul Hales wrote:
>>> From our experience (with a HP 2626-PWR) it hasn't been an issue.
>> PaulH
>
> Paul,
>
> Would you like to share wich phones you're using on this switch?
>
>
> Cheers,
> Kristof.
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