ZF7782 and PoE on second eth port

[jason_reich]

Hello, we have several ZF7782 still operating in our network, and I'm looking to utilize the second ethernet port with PoE.  We're currently running them with 802.3af, but want to use enable the second port with PoE.  I've read the spec sheet and install guide a few times, but still have questions.  

I'm only looking for basic 802.3af on the second ethernet port (not the high power 25W).  In the documents, there is mention of 802.3at and of 60W power supplies (which I'm guessing are non-standard 802.3at).  No mention of 802.3bt of course, as the APs pre-date that standard.

So to use 15W 802.3af on the second ethernet port, what power needs to be supplied on the primary ethernet?  Can it do that with 30W 802.3at?  Or does it need the Ruckus-specific 60w injector?

And are there any recommended injectors for this setup?  It doesn't seem easy to find the ruckus 60W injectors (902-0180-US00) as the ones listed seem to often have other specs or photos, so not clear of their actual power and compatibility. 

I've seen injectors on Amazon and elsewhere calling themselves "Ultra PoE+"that say they are 60W af/at/not-bt, but can't find much if that is a semi-standard or if that is what the ZF7782 is looking for.  (Example model: TrendNet TPE-117GI)  Any thoughts on those?

thanks in advance for any advice you can help explain this corner of haziness!