[Asterisk-Users] D-LINK PoE switch,

Joe Greco jgreco at ns.sol.net
Sun Nov 28 23:54:18 MST 2004


> As an alternative to the "expensive" PoE switches out there, I found the 
> D-Link Web Smart DES-1316 switch for just around $400.  Now, the issue 
> is, it does 802.3af power and, as I've found out through previous 
> discussions, this original 76?0 series phones (the non G variety) do not 
> use 802.3af.  So I'm assuming I just need to use the special cable thing 
> as per http://www.voip-info.org/wiki-Cisco+POE and it will work.  Is it 
> this simple to save myself $1000 over the next lowest price PoE switch?

To the best of my knowledge, both the 7960 and 7960G are Cisco pre-standard
PoE.  The 7970G is 802.3af.

Now, there's something you need to know:  802.3af compliant switches are not
supposed to just put out voltage.  There's some sort of protocol used to
negotiate power between a device and a switch, and without that, the switch
will not send power.

The little cable scheme on the Wiki assumes a "dumb" PoE injector which is
basically little more than a DC power supply dumping current on the spare
pairs to power an 802.3af compliant device.  Apparently devices will accept
power just fine even without negotiating, and that applies to Ciscos as 
well with the reversed-lead modification on the Wiki.

On a smart switch, however, I wouldn't expect it to happen, since power
will not have been negotiated.

You might still find that switch and a bunch of 3CNJVOIP-CPOD to be cheaper
than a Cisco compatible PoE switch, however.

Regards,

... JG
-- 
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.



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