Help powering a Catalyst 2950G-24-EI-DC switch

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Jul 19th, 2010
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Hi, first off I am NOT an IT guy. Im trying to help our IT guy out who is trying to use a Catalyst 2950G-24-EI-DC switch he has (inherited) but cannot locate the power supply for it.  I have the manual but cannot for the life of me find where the -36 to -72VDC the unit requires is suppossed to come from.  Is there a separate power supply for this?  I cannot seem to find a p/n if there is.  I can only find references to the "DC switch kit" which contains the connector and associated hardware only. Any help would be appreciated.



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infouser1 Mon, 07/19/2010 - 08:19
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I'm sorry, this is a most basic question. All we have here is a switch, where do the A and B power feeds originate? There has to be a rack, or power supply somewhere that supplies the -36 to -72 v to the switch. This unit was left over from a previous project and no one seems to know if there where any other pieces with or for it. Most of these Catalyst units simply plug into the wall, this model does not and must be supplied with DC power from somewhere. I am not familiar with these units, just trying to help a guy out and am missing something apparently.


infouser1 Mon, 07/19/2010 - 08:39
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Thanks for the speedy reply. This switch does not have an AC input connector like your picture. It has a back like this picture (65295.jpg)

The DC connector is where the normal AC one is pictured on the image you sent, the back rear corner. I have no idea where the DC power comes from. (65292.jpg) That is what I'm trying to find out.


burleyman Mon, 07/19/2010 - 08:44
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I am not firmiluar with DC power but I would think it would come frrom some type of power shelf or something along those lines.

Sorry I could not help further.


infouser1 Mon, 07/19/2010 - 09:02
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That's what I thought, however I can find no mention of anything resembling that (DC power source) anywhere in the manual, or the website, or the web, only instructions on wiring the plug itself. It has to exist somewhere. I will keep looking.



vmiller Mon, 07/19/2010 - 08:42
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Ok, this is a generalization since every data center is a bit different.

DC power to units can come off head of rack distribution panels that are

fed by main distribution panels. My point is that unless someone has

run the wiring from the distribution panel and connected it to the DC terminal

that was in the link I sent, you out of luck at this pont.

I would not mess around with DC power on my own. A good electrician

can lay things out for you.

johng1211 Tue, 08/24/2010 - 12:11
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Does anyone know where to purchase the green 4-wire terminal block plugs for the dc power connection?  Apparently, Cisco does not sell them seperately.(figure C-4 in the last message link)




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