Hi ,
power injector is used to supply the power through ethernet .
Power injector has two ethernet connector one going to switch and one going to AP
So packet travells from switch to power inector and power injector to AP ...
So cable between power injector and switch is to carry etherent packet from switch to AP ....
so under normal condition
wall- power adapter--Ap------ether cable ------switch
now with power injector
---------------------------------------------
|
Power plug
|
|
AP------------ power injector ----------Switch ---backbone
I hope this helps
Nilesh