power injector with SPA508g

Unanswered Question
Feb 17th, 2012
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I decided to edit this since it got moved to a different place where it might not be understood:

I have a UC320w phone system. I have SPA508g phones. I have a cisco POE switch next to the UC320. But, I have one far location that has one ethernet port and we want 3 computers and the SPA508g phone. I don't have a POE switch and I'd prefer to put the switch before the phone. (the out port on the phone is 10/100 where I'd like the link to the far switch to be gigabit).

The SPA508g didn't come with power cords. I know I can get them.

But I happen to have an Aironet 1200 access point power enjector: AIR-PSINJSYS1200. I think the aironet needs 48 volts, so I assume this power injector provides that (or up to that?).

Is that ok to use this power injector with a SPA508g? Will it just draw whatever it needs or is that power enjector too much power? I seem some documentation that says the AIR-PSINJSYS1200 will work with a access point that requires less power, but I don't see any other documentation.

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Mark Smith Tue, 02/21/2012 - 16:52
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Is it unknown if the power injector will work to power the phone? I guess I should have just ordered the power cord by now, but I thought I might get a quick answer here...

David Harper Tue, 02/21/2012 - 17:12
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Unfortunately this is the wrong area of the community to pose the question.  While I believe the aironet power injectors present a standard IEEE PoE interface to the device, I can say that for certain.  Certainly those power injectors are only supported for use with the Access Points, and the people who hang on on this community are unlikely to be familiar enough with the product to say for sure whether it will work.  If the injector does present an IEEE PoE interface then the phone should work fine, but I can't confirm that for you.  You might want to try posting a question to the wireless forum at




cindy toy Tue, 02/21/2012 - 19:33
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Hi Mark and David,

I have moved this discussion to the Other Wireless Mobility area so it is not necessary to re-post.


Cindy Toy

Cisco Small Business Community Manager

for Cisco Small Business Products


twitter: CiscoSBsupport

Mark Smith Tue, 02/21/2012 - 23:47
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Ok, I'd still love some confirmation but from what I see now this power injector was made before the POE IEEE standard and the polarity is reversed from the standard. This would mean that I can't use it?


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