The other day I was asked about powering an IP camera over Ethernet. It turns out to be a bit confusing so I thought it would be helpful to write this down and un-confuse it.
First of all there are many different types of IP cameras. Some of the new cameras conform to the IEEE standard, but many of the older cameras have unique voltage and current requirements.
In some cases the camera manufacturer will recommend and even provide a Power over Ethernet (PoE) solution. For example Axis and Sony make it easy because they have a solution for many of their cameras. When the camera manufacturer doesn't suggest anything, you have to do some investigation.
I'm still working on the details and will get back with more information after the weekend.