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Cisco 3560 POE switch not providing power to Cisco 7960 phones

Posted on 2010-08-27
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Last Modified: 2012-05-10
I have a Cisco 3560 POE switch, Cisco 7960 phones are connected to the swtich but only one phone shows that it is being powered by POE.

This is a brand new out of the box, CDP is enabled and power inline is set to auto.

Not sure whats happening, I have very little experience with Cisco. If anyone is able to help that would be great, thanks for your suggestions.
POE.jpg
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Question by:carloc
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by:jesse_7271
ID: 33546587
What is the distance to the phones?
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by:carloc
ID: 33546680
the farthest phone is approxiamtely 40ft away, the phone which is displayed in the imagine is roughly in the middle. THe Phone closest to the swtich in the server room is not showing POE.

I have tried connecting a phone directly to the switch put it still does not recieve POE either. The phones are also connected to power adaptor.
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Expert Comment

by:luc_roy
ID: 33546843
Is this the case with all phones or just this one?
The wire you are using is it CAT-5 or CAT-6?
Have you attempted it with different wires?
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Author Comment

by:carloc
ID: 33546863
the ethernet cable has been swapped out with the same result using cat 5 and cat 6.
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by:lrmoore
ID: 33546908
If you have a 3560V2 switch, it is 802.3af *only*
If you have old phones, i.e. 7960, they are pre-standard PoE *only*
You have a mismatch.
What is the exact model number of the switch?
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Author Comment

by:carloc
ID: 33547071
I am getting the information on the swtich model. Question though, if the 7960 phones are pre-standard why would one still show as powered with POE from the above image?
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Expert Comment

by:lrmoore
ID: 33547416
7960G vs 7960 ?
Are all the phones the exact same?
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lrmoore earned 500 total points
ID: 33550267
No, all phones are not the exact same. Older phones require pre-standard PoE, newer phones can use either pre-standard or 802.3af, newest phones are 802.3af only.
7960 = PoE
7960G requires power brick. When this phone was made, PoE over Gigabit did not exist.
From the 7960G cut sheet
"48 VDC required, supplied locally at the desktop using an optional AC to DC power supply (CP-PWR-CUBE-3=)"



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Expert Comment

by:shameer2000611
ID: 33558438
7960G phones will consume 6.3 w and this will be same as the old 7960 phones.
More over CP-PWR-CUBE-2= is using when there is no PoE available.
Use the show log privileged EXEC command to verify that the powered device is not causing an overcurrent condition on the port. Verify the symptom precisely: Does the phone initially power on and then disconnect? If so, the problem might be an initial current surge that exceeds a current-limit threshold for the switch port.

If no way better u can you can raise a RMA with cisco for replacing the switch.
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Author Comment

by:carloc
ID: 33560633
Thanks for your suggestions, I will work to find answers to the issue you have mentioned and post the results as soon as possible. It may take a little time because the office is in a different state and I am working with another person to resolve this issue.
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Expert Comment

by:jamesddavis
ID: 33970100
We have a similar issue.

We tried replacing some 3560 PoE 24 port switches with 3560v2 24port PoE switches and had the same issue. After being the phone for a couple hours with TAC they had us put a newer version of the IOS on the switch. This resolved the issue with no power getting to the phones over the network, but then the phones would never come fully up, they would power up, but never come fully up.

Suggestion would be try different IOS verisons for that switch. I am working with Cisco TAC currently to try and get the issue resolved. If I get anything more I will post back.
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Author Closing Comment

by:carloc
ID: 34103851
It turns out that some phone we older models and would not work so they required their own power supply. Thanks for pointing in the right direction.
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Expert Comment

by:skynetop
ID: 35062755
We had exactly the same issue - I had several 7960Gs that would work and several that would not, all were identical as far as I could tell - even down to the hardware revision (c0).  I ended up changing the IOS on our 3560V2 from 12.2(50)SE1 to 12.2(55)SE1 which ended up resolving the issue, now all phones consistently power up and they seem to get detected for PoE even faster than before.
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