Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

300 Series POE and legacy devices

Greetings;

I convinced the powers that control my paycheck to stick with Cisco for small POE switch deployment.  Yay!

So, I opened up my shiny new piece of hardware (a SF302-08MP aka SRW208MP-K9-NA), plugged in a Cisco 1230 and an 1121 AP AND... nothing.

I thought to myself, looks like Cisco is following the 802.af standard.  I grabbed my crimper, swapped pins 4 and 5 with 7 and 8, and... nothing... again...

Now, the whole reason I pressed so hard for this equipment is that I wanted to be certain that our Cisco devices would be supported.  The weird part is that an older Linksys (by Cisco or whatever) POE switch works just fine.

Knowing that there are two types of 802.af (one that delivers power via pins 1,2,3, and 6, and the other 4,5,7, and 8), it does not make sense that a switch (especially a Cisco switch) that says it complies with 802.af, would only comply with one type (I'm pretty sure the standard requires both).

Do I have a faulty switch, or an unhealthy attachment to a company that I adore?

  • Small Business Switches
8 REPLIES
Bronze

Re: 300 Series POE and legacy devices

Is it correct to say that POE works for some devices and just not these APs?

Did it work when you tried a straight through cable?  Are you swapping the pins to make this work with Cisco proprietary POE?

Hope I understand what you are trying to do.

Thanks!

Andrew Lissitz

Bronze

Re: 300 Series POE and legacy devices

The 802.3af standard has 2 modes, Mode A using the data pairs 1,2 - 3,6, Mode B using the spare pairs 4,5 - 7,8. However, these modes can not be implemented simulataneously on the device according to the standard. Having both modes simultaneously is part of the 802.3at standard.

For more information, please refer to this document : http://en.wikipedia.org/wiki/Power_over_Ethernet

On the Cisco Sx300 series PoE switches, Mode A is implemented, meaning that PoE is enabled on pins 1,2,3 and 6.

Hope this answers your question.

New Member

Re: 300 Series POE and legacy devices

Greetings!

I thought that my first post was clear, but apparently not.  I understand the two types of 802.3af standards very well.

Here are a few direct questions:

1) Did Cisco put out a POE switch that does not work with their legacy clients?

2) Is the hardware present within the switch for there to be a firmware fix for this (in other words, is the functionality for type b present, but not enabled via soft/firmware)?

3) Aside from wanting people to buy new gear, is there a reason that Cisco is moving away from backwards compatibility?

I hope that clarifies my post.

Cisco Employee

Re: 300 Series POE and legacy devices

Matt,

The 1230 and 1120 APs are older and were developed before there was an 802.3af standard. They support Cisco pre-standard POE and not 802.3af POE. See table 5 in the following document link - http://www.airquay.com/pds/airquay_catalog/Power.pdf.

The 300-series switches are 802.3af compliant devices and deliver power to endpoints per the standard. It can power any 802.3af standards-compliant device and does not power non-standard devices.

Ivor

New Member

Re: 300 Series POE and legacy devices

Looks like you're making your own cables, but PanOptic Technology makes quite a few elegant solutions for  providing/extending power to both PoE standard/non-standard and non-PoE  devices over Cat-5 cabling:
http://www.panoptictechnology.com/network-smart-adapters/
http://www.panoptictechnology.com/network-poe-extenders/

Good luck!

Re: 300 Series POE and legacy devices

Hi, My name is Eric Moyers. I am a Network Support Engineer in the Cisco Small Business Support Center.

Currently there is no testing from Cisco to certify the use of any third party PoE adapters or extenders with any of our Small Business Equipment like the SF300 switches. While there are several out in the market, while using third party equipment that has not been certified can potentially work, they have an equal chance of not working or damaging equipment. Before using such devices I would make sure that they will replace any equipment that is damaged from the use of their products, because Cisco may not depending on the circumstances.

I am by no means saying that customers can not use third party equipment. I just want all of our customers to have all of the information.

Eric Moyers

Cisco Network Support Engineer

1-866-606-1866

Cisco Employee

Re: 300 Series POE and legacy devices

Please note that the 200 and 300 Series switches now support Cisco Legacy POE as of September 2011, allowing it to deliver power to 7960, 7940, and other pre-standard phones and APs. Details provided at the following link:

https://supportforums.cisco.com/docs/DOC-18337

New Member

Re: 300 Series POE and legacy devices

Ivor,

Thank you for the information on Cisco Inline Power support for the 200 and 300 series switches with the firmware upgrade released in Sept. 2011. However, it appears to have only been released for certain models in the 200 series. To be specific, the latest firmware available for the SG200-08P as of today is 1.0.1.0.

Does Cisco have any intentions to support CIP on the SG200-08P, or is it not possible for that hardware?

Tom

2739
Views
0
Helpful
8
Replies
This widget could not be displayed.