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New Member

Inline Power on a 3550PWR-24

Does anyone know the pinouts for the 3550PWR switch. Im trying to power an orinoco AP and i want to know if it will work.

7 REPLIES
Cisco Employee

Re: Inline Power on a 3550PWR-24

CAT3550 supports Cisco inline power implementation. Does Orinoco AP support 802.3af or have their own implemetation for inline power?

http://www.cisco.com/warp/customer/cc/pd/si/casi/ca3550/prodlit/c3550_qp.htm

New Member

Re: Inline Power on a 3550PWR-24

The AP support 802.3af. As far as I know the 3550 does not. I have heard that the 3550 supplies power on the opposite pins than the 802.3af standard does.

is this true?

New Member

Re: Inline Power on a 3550PWR-24

Does anyone have any ideas on this yet ??

Gold

Re: Inline Power on a 3550PWR-24

Cisco's inline power is not just delivered in the same cable sheath as the data pairs: the power is actually delivered over the same wires as the data. It does NOT use unused pairs in a Cat5 connection.

Thus, pairs 2 and 3 (orange and green, in a EIA/TIA 568B jack), or pins 1, 2, 3, and 6 in the RJ-45 connector, are where the power is, on Cisco 10/100 connections.

Pairs 1 and 4 (blue and brown) are NOT used; so there is no power on pins 4, 5, 7, and 8.

I believe the 802.3af inline power uses the unused pairs to deliver power.

Not sure what your need is, but there's a company out there, Red Hawk, that makes media-converter-like power injectors for 802.3af, Cisco, and 24V proprietary inline power application. Good if you want inline power, want to be able to mix and match power standards from a central location like a wiring closet, and want to use regular switches. Check out the info at this link:

http://www.red-hawk.com/products/copper/network/bl8000.htm

Hope this helps.

New Member

Re: Inline Power on a 3550PWR-24

Are you sure??

I dont think you can send power and Data over the same pairs. I would have to think that this would have some kind of negative effect on the data.

Gold

Re: Inline Power on a 3550PWR-24

Yes, I'm pretty sure.

Here's a couple of links on how the Cisco switches do it (Cisco proprietary on the Ethernet pairs), and the 3550-24 PWR's lack of support for the IEEE 802.3af standard (which means it uses the proprietary method):

Understanding the Cisco IP Phone 10/100 Ethernet In-Line Power Detection Algorithm

http://www.cisco.com/en/US/products/hw/phones/ps379/products_tech_note09186a00801189b5.shtml

Basically, while the Cisco switches use the Ethernet pairs, they don't put full power onto a line until they detect a compatible device at the other end.

Cisco Catalyst 3550 Series Switches Q & A

http://www.cisco.com/en/US/products/hw/switches/ps646/products_qanda_item09186a00800913d3.shtml

If you search for "inline" in the second link, you eventually get to this:

"Q. Does the Cisco Catalyst 3550-24 PWR switch support the upcoming 802.3af inline power standard?

A. This switch will support the Cisco inline power implementation and 15.4W/port on all 24 ports. 802.3af compliance cannot be claimed due to the current status of the proposed standard (draft form) and litigation involving an alleged patent violation for the power disconnect portion of this standard. Full 802.3af compliance is dependent on the outcome of this litigation. Vendors claiming current support for this standard should also inform their customers of the risk associated with draft standard claims. The 802.3af standard is expected to be ratified Q3CY03. Backward compatibility will ensure that previously sold Cisco IP phones and wireless access points will be compatible with the new Cisco Catalyst 3550 inline power switch. Development of an 802.3af inline power Cisco Catalyst 3550 switch has been difficult because of the uncertainty that has existed in the formation of the final IEEE standard."

For what it's worth, I have interconnected all sorts of non-powered devices, both non-Cisco and Cisco, to inline power 10/100 ports on 3524XL PWR switches. All devices work fine, and only the Cisco wireless access points and IP Phones draw power. Nothing is getting fried, and no data is being lost or affected on those connections. It really works.

And when I can't cost-justify a full 24-port switch to provide Cisco inline power, or when I need non-Cisco inline power for a device, that's when I bring in the Red Hawk equipment.

Cisco's inline power patch panel puts power on the unused pairs, according to link #1, but I think only Cisco's phones and access points, or Cisco-power compatible devices can use it. If you have a high density of Cisco inline-power devices deployed in a limited area (100-meter Cat5 radius), and they all connect to NON-Cisco switches, then I guess the patch panels make sense. I've never had occasion to use one of these, though.

Hope this helps.

New Member

Re: Inline Power on a 3550PWR-24

Back in Jul 2003, Cat3550's did not yet support 802.3af -- is that still the case, or has Cisco gotten any closer (if so, how close)?

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