My recollection of the marketing fluff was that we would just use our
legacy network (cables) and the devices at both ends would figure out
whether they were sourcing, sinking, or neither. In the case of the
501, it's the special Polycom cable, either with or without provision
for an AC power adapter, that powers the phone. That's what I meant
by saying the '501' itself is not compliant with 802.3af -- it needs
a separate thingamajig [tech jargon :)]to be powered.
Anyway I had hoped that I could just plug a CAT-5 patch cable from my
RJ45 wall outlet into the phone.
On Mar 5, 2006, at 5:17 PM, Michael Welter wrote:
As I understand 802.3af, the phones go through a negotiation with
the unit supplying the power. I don't think it's a matter of
-48VDC on a particular pair. I remember a schematic from years
ago--it had each of the receive pair and the transmit pair going
into a transformer winding, and that winding had a center tap for
PoE. This is not something that *I* am going to screw with.
The IP501 telephone set is the same for both PoE and local power.
With the PoE cable, the 802.3af electronics (the negotiator) is a
plastic thing in the cable. For the local power, there is a
plastic thingie toward the wall end of the cable, and you plug the
wall wart into the plastic thingie. <Notice the advanced technical
jargon here>
With local power, there is still only one cable one the desk--the
power plugs into the cable towards the wall. Except for a power
interruption, this has all the advantages of PoE.
William M Conlon wrote:
I saw that Polycom offered a cable (not stocked anywhere), at $40
a pop for 802.3af connections. That's what made me think the
phone itself is NOT 802.3af compliant.
Presumably, for $40, there's more than a fuse in that special cable.
On Mar 5, 2006, at 4:31 PM, Paul Hales wrote:
For Polycom IP500/501's and IP300/301's you need a special
polycom POE
cable.
When you buy Polycom phones you can usually specify POE or
powerpack.
PaulH
On Sun, 2006-03-05 at 16:23 -0800, William M Conlon wrote:
When I bought two Polycom 501 SIP phones, I naively thought they
were
Power-over-Ethernet (IEEE 802.3af) because they were "powered over
ethernet." Silly me.
Polycom must have some odd voltage or funny way of injecting the
power, because the POE switch I bought for them (Netgear [EMAIL PROTECTED])
won't power them, though if I use the Polycom-supplied AC
adapter and
ethernet power injector cable, they work with the switch in either
its powered or unpowered ports.
Anyhow, I hadn't seen any mention of how people power these phones,
as I had planned on centralizing phone power on a UPS to supply my
Asterisk server and POE switch. Now the question is:
Can the Polycom AC-powered injector be used with a standard
ethernet
patch cable:
switch :: Polycom injector cable :: RJ45 coupler :: patch
cable ::
Polycom 501
which would allow me to power the Polycom AC adapters by my
UPS. Or
do I need to provide a UPS at each phone and run the ethernet like
switch :: patch cable :: RJ45 coupler :: Polycom injector
cable ::
Polycom 501
thanks.
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Bill
William M. Conlon, P.E., Ph.D.
To the Point
345 California Avenue Suite 2
Palo Alto, CA 94306
vox: 650.327.2175 (direct)
fax: 650.329.8335
mobile: 650.906.9929
e-mail: mailto:[EMAIL PROTECTED]
web: http://www.tothept.com
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--
Michael Welter
Telecom Matters Corp.
Denver, Colorado US
+1.303.414.4980
[EMAIL PROTECTED]
www.TelecomMatters.net
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Bill
William M. Conlon, P.E., Ph.D.
To the Point
345 California Avenue Suite 2
Palo Alto, CA 94306
vox: 650.327.2175 (direct)
fax: 650.329.8335
mobile: 650.906.9929
e-mail: mailto:[EMAIL PROTECTED]
web: http://www.tothept.com
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