PoE Switches - How Does PoE Recognize Devices Connected Requires Power?

[shahreezal.ahmad]

Cisco PoE Switches Enquiries

1. How does PoE switches recognize which devices connected requires power? i.e. When you plug a Cisco IP Phone, the PoE switch will power the Cisco IP Phone but when you plug in a computer, it does not power it. What is the mechanicm behind that?
   
2. How does PoE switches know to provide power to PoE devices if the switch CPU is saturated (100%), does it affect PoE devices (IP Phones) ?
   

[Leo Laohoo]

http://www.poweroverethernet.com/