Using CP-7937G on Power Adaptor / Power Splitter

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Jun 15th, 2009
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The CP-7937G IP Phone configured on out network is not powering on with power splitters and power adaptors supplied along with it. It only powers on via the POE port from a POE switch. Cisco TAC supplied all possible RMAs but none of them helped in powering on the phone through Power adaptor / splitter. We also tried to power on the phone using power splitters and adaptors of another brand new CP-7937G phone. Please advice.

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Rob Huffman Mon, 06/15/2009 - 04:38
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Hi Devang,

Did TAC supply a new 7937? It almost sounds like this bug that only effects the 7937 when using External Power;

CSCsh35000 Bug Details

7937: Cannot register if disconnected ethernet is connected back


An externally powered 7937 keeps displaying the Cisco logo and "Configuring IP" message


The ethernet cable is disconnected



Hope this helps!


devang_dand Mon, 06/15/2009 - 05:50
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Hi Rob, thanks for the reply. I dont think it should be a bug or something. The phone does not power on at all when we connect the power adaptor. There are no messages displayed on the phone. However, with the POE switch, it powers on within a minute.

christianojum Mon, 06/15/2009 - 04:41
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From what you explained, it is likely, that the poer component (circuit) of the 7937 ip phone is bad. to confirm this, try to use the same power brich to power another 7937 ip phone and see if it will come up

devang_dand Mon, 06/15/2009 - 05:48
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Thanks for the reply.. Yes, we did try all the possibilites, but all in vain.. We changed the Power Socket, changed power splitter, changed power adaptor, changed location of the phone, changed the main phone hardware, but no results at all.

christianojum Mon, 06/15/2009 - 06:41
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Let me get you right. when you say 'changed the main phone hardware, but no results at all',this means that the problem is not just with a particular 7937 ip phone. It happens to more than one. Am I right?

devang_dand Mon, 06/15/2009 - 21:16
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Yes, you have got it right.. All Cp-7937G phones are facing this issue..

christianojum Mon, 06/15/2009 - 23:24
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My dear,

I shuldn't be asking you if there is clean power supply on the power sucket you are using because I know there should.I also do not want to beleive that there is factory fault in all the CP-7937 you pourchased (though it seems to be). But to claer all these doubt, if you have any site where you are using power brick to power a CP-7937, you should take one of these phones having the problem to the site and see if it will come up.Otherwise,i think you should continue with the TAC case which you have raised. Please, I realy need to know how this issue is resolved.


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