7971 Phone will not power on

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Feb 3rd, 2009
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I have a cisco 7971 Phone plugged into a 3550 POE switch (there are 5 other POE 7940's and 60's on the same switch) and the 7971 only flashes the speaker light for aproximately 10 seconds, then flashes the mute button for about 1 second.


It continously recycles through these two buttons. The LCD screen never comes on . . I have plugged other POE phones into the same port and they power up fine. I also have confirmed the configuration of the switchport (which is the same throughout our organziation).


Does anyone have any idea what the alternating mute/speaker light indicates?


I appreciate any responses.


Thanks,

JP

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Rob Huffman Tue, 02/03/2009 - 09:49
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Hi Andrew,


I have always found this hard to explain, but I will try :)


Cisco PoE switches are not all created equal. Older models like the 3550-PoE that you are using only support what is called "Cisco Pre-Standard PoE" and do not support the IEEE Standard which is referred to as IEEE 802.3af PoE.


Now for the fun part?? Different models of Cisco IP Phones have different PoE requirements sometimes called "Classes" These Classes require different amounts of power supplied by either "Cisco Pre-Standard PoE" or IEEE 802.3af PoE. New Models of Cisco switches are backwards compliant to support both PoE modes but Old Models like the 3550 only support the one Pre-Standard mode (confused yet?)


So when using the Old models like the 3550 you always have to be careful of what IP Phone type you can or can't support.


Have a look;


The 7940G/7941G and 7960G/7961G are class 2 devices (7.7 watts) power requirement.The 7941G works with Cisco Pre-standard PoE and with IEEE 802.3af PoE.



The 7971G phone is a class 3 device (15.4 watts) and only supports IEEE 802.3af PoE.These are not configurable settings.



Hope this helps!

Rob


markcarat Tue, 02/03/2009 - 09:52
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which IOS your 3550 is running? We have 7971 and it wont power up unless we use a brick. We recently upgraded the 3560 IOS, POE started to work.


Mark

berridgemfg Tue, 02/03/2009 - 11:21
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Thanks to all for the advice. I will get back to you all in let you know what works.


Thanks!

JP

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