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Community Member

PWR-CUBE question


I really hope someone knows the answer to the following, it is a little bit more technical than dealing with the phone and its configuration.

Does anyone know what the difference between the old school PWR-CUBE and the PWR-CUBE=2 and PWR-CUBE=3 is as far as electrical terms. I have heard that each of the power cubes deliver exactly the same amount of power, in the same way.. 48v (100-240v) with the same amperage and the such. Just that the tips were different for the different models. edit: After unplugging my old pwr-cube just for safeties sake I tried to insert it into the 7970 and can see clear as day that the tip just isnt long enough, and the plastic end is just too large.

Turns out I have a spare tip that fits perfectly into the 7970, but have the older PWR-CUBE. I am a bit of an electrician so replacing these tips and getting positive and negative correctly will not be hard for me at all.

What I'm wondering is can I do this? Can I talk an old first gen PWR-CUBE and put my new tip on to work with the 7970. Or is the output type different aswell.


Hall of Fame Super Red

Re: PWR-CUBE question

Hi Don,

I'm guessing by this and your previous post (earlier today) that the power injector is not working with the 7970 or perhaps you are just trying to determine the nature of the problem. I hope that we didn't guide you down the wrong path with the injector :(

Here is a tech note of what Power Cubes to avoid using with the 7970 (You are not going to love this but I thought that you should see it);

Guidelines for Powering the Cisco IP Phone 7970 Series

External power - Provided through the CP-PWR-CUBE-2 external power supply

The CP-PWR-CUBE-2 (341-0081-01) external power supply is compatible with other Cisco IP Phones.

The older power supply, CP-PWR-CUBE= (34-1537-01), does not provide sufficient power to the Cisco IP Phone 7970 Series and will not connect to the phone.

From this 7970 doc;

Hope this helps!


Community Member

Re: PWR-CUBE question

I'm not deeply upset, I'm more glad I know for sure now what I have to do.

I'm really stumped at why this injector isn't working, it provides class 3 power, at the 15.4 watts. The phone does power up but there just isn't any back light even when I could make out that the slider was about 1/3 of the way up the scale (by spending like 10 minutes tipping the phone until i caught it at just the right angle). Does it seem possible to you that the backlight on the screen is broken? Or is this unlikely seeing that the screen itself was indeed displaying data, just nearly impossible to see data.


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