Wiznet POE Question

NWCCTV

I see Parallax is now carrying the Silvertel POE Module. This is a step in the right direction for a project I have had on my mind for several years now. However, I need 12V. The Wiznet Ethernet board says it is compatible with the AG-9050 but no mention of the AG-9120 which is in the same line but is 12V. Does anyone know of a way I could make the Wiznet Module work with the AG-9120 without compromising anything?

Franklin

Real POE is 48vdc so anything less has to be designed for the purpose. the only thing you need is to make sure you have regulators that can reduce the voltage to the level you require. If you plan to supply 12v on the POE lines just make sure you have a 5v regulator on the input to the wiznet.

xanadu

Dude this is where the fun starts! Compare the datasheets. The Parallax module outputs 5v and steps down from IEEE 802.3af. So can you tap 12v in-between, or can you boost the 5v. The real questions is how much current do you need the device running at 12v? If you can't do it with that module check out 802.3at (PoE+) it's pretty hardcore, it's more like the CCTV siamese two conductor could do.

aquaman

This looks similar or identical to the Arduino PoE module which supports 802.3af on their ethernet shield. It is not the same as the 'PoE' that simply
injects any arbitrary DC voltage into the Rx/Tx pairs. I was fooled by products that supported 'PoE' but fortunately didn't fry anything with real PoE. Be careful!

802.3af runs an isolated -48VDC or -54VDC up to 15.4W. For this, you'll need a corresponding PSE supply on the other end.

Unfortunately, this card appears to outputs only 5V. To get 12V, you'll need an external converter to step it back up.