POE and 7940 ip phone

Unanswered Question
May 29th, 2008
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I have a 2811-ac-ip with a NME-16ES-1G-P card install I can get a 7941 to power up, but the phone I have are a 7940 and they will not power up. The swith is running 3750 Software (C3750-IPBASE-M), Version 12.2(35)SE5. Please help

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thisisshanky Thu, 05/29/2008 - 08:17
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Have you tried powering this particular phone on another inline power switch ? Just wondering if its a bad phone?

Rob Huffman Thu, 05/29/2008 - 08:32
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Hi Douglas,

It sounds like this bug (Thanks Met!);

CSCsi70300 Bug Details

NME Etherswitch Service Module Not Detecting Pre-Standard Devices


Pre-Standard POE devices are not powering up, link is down/down.


PreStd POE device must be connected to Etherswitch Service Module (ex. NME-16ES-1G-P) running 12.2(35)SE2.


Downgrade IOS to 12.2(25)SEE3

Further Problem Description:

Althought the NME runs 3750 IOS, the problem is not seen on a 3750 switch.

The IEEE 802.3af devices function fine (ex. 7961, 7941), only Pre-Std are affected.

Hope this helps!


qwest5555 Thu, 05/29/2008 - 10:56
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Downgraded switch to IOS to 12.2(25)SEE3

Everything work great !!



Shane Kirby Thu, 05/29/2008 - 11:25
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If you need to run a later version of IOS for other features this defect is resolved in 12.2(40)SE or later.

mattman04 Thu, 05/29/2008 - 14:18
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I'm seeing similiar behavior on my Cisco 1801.

POE - power supply is connected and POE LED is green, but when I connect 7941 phone it does not power up.

I'm running IOS Version 12.4(11)T4.

The inline power config is set for auto on all ports and a 'show power inline' sees an 80 watt power supply, but nothing allocated to any of the ports.

Any thoughts would be greatly appreciated.



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