[Tfug] PoE supplies/injectors

[Bexley Hall]

Hi,

I'm curious as to the type of *typical* support provided PoE.
I assume legacy installations use midpoint injectors on
*select* drops (to eliminate the cost of replacing existing
switches)?

Or, is it more typical for the switch to be replaced to
provide PoE to *all* drops?

Now, the kicker:

Are there any "smart" injectors (midpoint or endpoint) where
"something" can control the delivery of power *to* the PD's?
I.e., so that I can selectively apply/remove power from
individual drops?  And, ideally sense/control the class
negotiated by the PD (i.e., so I can *manage* power instead
of just providing it)?

Suggestions for appropriate searches that might turn up
this sort of information appreciated.

Thanks!
--don