[asterisk-users] PoE - IEEE 802.3af

[Dave Fullerton]

Mike wrote:
> Hi,
>  
> I'm not clear on how to use Power--over-Ethernet, specifically with Polycom
> phones.
>  
> What I understand, is that by buying the Polycom 501 with the 802.3af cable
> bundle, I simply connect my phone, through the Polycom provided "special"
> RJ-45 cable, into a PoE capable switch, and voilà!
>  
> Is this true?  And if so, what happens when the Phone doesn't connect
> directly to the switch? (let`s say there is wiring in the wall that goes to
> a patch panel, for example.  Do I need to change all the wiring in the
> office?)
>  
> Mike


Yes it is true that you need a special cable (provided in the 802.3af 
bundle). This cable is black, about 4 ft long and has an RJ45 plug (goes 
into the phone) on one end and an RJ45 Jack (plugs into the patch cable) 
on the other. Near the RJ45 jack there is a little black box that does 
the power conversion from 802.3af into whatever the phone needs. There 
is also a (not sure what it's called) spot for you to plug in an AC 
adapter if necessary. There's a good picture of one here:
http://voipstore.atacomm.com/Shops/ViewItem.aspx/27934028032-38040890624.htm

As long as you have CAT5 or better cable between the switch and the RJ45 
jack on the special cable you will be fine. Using a patch panel and a 
wall jack is also fine as long as it is CAT5 or better. You just can't 
have another switch or hub between your POE switch and the phone.

-Dave