XPost: alt.home.repair, sci.electronics.repair   
   From: wb8foz@panix.com   
      
   "Carlos E.R."  writes:   
      
      
   >Notice that Ethernet cameras are normally PoE. Maybe you haven't   
   >noticed, this means "power over ethernet". Two of the wires in the   
   >ethernet connection (RJ45) are used to provide electricity to the   
   >camera, thus saving in an extra connection and hardware. But means you   
   >mean to install a PoE Switch to provide this special Ethernet connection   
   >(which can of course power a number of cameras)   
      
   Not quite.   
      
   IEEE 802.3af-2003 uses Phantom Power of Olden-Daze .   
   The transformers at center-tapped;   
      
   Secondary winding:   
      
   ---------------  Bl/W To camera via CAT 5/6   
   \   
   /   
   == CT +   
   \   
   /   
   ---------------  W/Bl To camera via CAT 5/6   
      
   The unshown primary windings provides the data. The CT is   
   connected to the power supply.   
      
   This is just the data TO the device; an identical second one   
   is for the data back FROM the camera. Its CT will be the power   
   supply negative.   
      
   This is replicated at the camera.   
   --   
   A host is a host from coast to coast...............wb8foz@panix.com   
   & no one will talk to a host that's close..........................   
   Unless the host (that isn't close).........................pob 1433   
   is busy, hung or dead....................................20915-1433   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)