Active or Passive PoE, That is an Important Question

When regarding to Active PoE or Passive PoE, many people may get confused. Active PoE is 48V PoE which meets the IEEE802.3af or IEEE802.3at Standard while Passive PoE usually refers to any device using PoE that is not IEEE802.3af or IEEE802.3at.

Power over Ethernet ( PoE) use Ethernet cables to supply power to other PoE capable devices on the network, such as Wireless Access Points, IP cameras, VOIP phones, and other switches, etc.  This feature allows the user to power these devices without the need for a separate power supply or the need for an electrical outlet near the powered device.

Active PoE (48V PoE)



If your PoE device uses the PoE standard 48V IEEE802.3af or IEEE802.3at, it is considered to use Active PoE.This means that the device will check the power coming in, and, if it doesn't meet the device requirements, it just won't power up.

PoE standards have been optimized for safety.  In addition to a safe voltage range, the devices must communicate according to established procedures.  Before providing the supplying voltage, the PoE power supply unit tests the connection IEEE802.3at then does a “handshake”, meaning it checks to ensure the power is compatible between the PoE sender and the receiver, and won’t power up if the receiver does not acknowledge.

Passive PoE 

Passive PoE usually refers to any device using PoE that is not IEEE802.3af or IEEE802.3at.  This includes devices such as cameras and radio antennas that run on 24V PoE.  Passive PoE does not perform a handshake, so it is extremely important to know what PoE Voltage your device requires before plugging in the Ethernet cable and powering it up. If you connect the wrong voltage you may cause permanent electrical damage to the device.  So it's important to choose the right PoE Swithes.