Power over ethernet / inline power to Cisco 7960 IP phone

Dear all,

I am testing an Orinoco AE 12 Port DC Injector which looks like an OEM
PowerDsine 4012 and I am trying to connect some Cisco 7960 IP phones
to it via inline power. To plug an ethernet cable straight between the
POE hub and the phone did nothing. So after some search at Cisco's web
site (http://www.cisco.com/en/US/products..._guide_chapter09186a00800b607e.html#wp1003764)
and other documents and specs readings, I switched lines 4&5 with 7&8
and vice versa of the cable (just to reverse polarity, without really
knowing what '+48 Volts return' and '+48 Volts source' at the Cisco
page above means...) - and now some relais (?) sound click-click
inside the IP phone can be heard, but the phone still doesn't work.

My guess is that Cisco uses its own propritary way, but I am not
sure...

Any help would be appreciated!

Thanks, Bernie

 

You are right, Cisco use its own L2 propritary protocol CDP for
detecting the any direct connected Cisco device (i.e. Cisco IP phone,
router, switch, etc).

A in-line powered switch will send a little bit of power and CDP to its
neighbor (FE) to detect any Cisco IP phone, if the phone response, the
switch send DC power to the phone for boot up process.

 

Thanks, Jerry, for your answer!

I found at http://www.powerdsine.com/Documentation/SelectionGuide/SelectionGuide.pdf
that there exists a simple passive splitter to connect an Cisco IP
phone to the PowerDsine 6000 midspan series. This splitter is sold
e.g. at http://hardwarecentral.dealtime.com/xKW-PD-PS-401/NS-1/linkin_id-3013120/GS.html
- it looks like an ethernet adaptor with some crossed internal
connections (they wouldn't sell an adaptor with all lines linked
one-to-one, would they? ;-) ) My test injector device seems to be a
PowerDsine from the 4000 series. (4012 w/ 12 ports)

So the two questions are: 1. cable layout of this adaptor? (just 4/5
switch with 7/8?) and 2. is the 4012 cabable of serving Cisco's Ip
phones with that adaptor?

Thanks, Bernie

 

Bernie,

Tell you the truth, I am not sure about this product from PowerDsine and
the wiring. I know that Cisco sell something call Power Patch Pannel,
what it does is the ethernet connection from the switch will connect to
the power patch pannel, and the Cisco IP phone will connect to the power
patch pannel. Since this is also a Cisco product, (I think) CDP is also
installed on the power patch pannel.

When I am doing the VoIP project, I found that the cost of the power
patch pannel is not much different from replace the switch to a Cisco
in-line powered switch (w/ all the port cap. I have). And we decided to
buy power-cube from Cisco to power the phone for the user instead (of
course, the user shouldn't unplug the power-cube from the outlet). My
thinking was if I am going to replace switch to in-line powered later on
(within the next 2 yr), I also have the cube on the user's desk as the
backup power source.

jerry