What is passive PoE and active PoE?

At first we need to know that what is PoE. Power over Ethernet (PoE) is refer to use Ethernet cable to supply power to other PoE capable devices on the network, such as Wireless AP, IP cameras, VoIP phones, and industrial 4g router, 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. Here we use industrial 4g router as example to give better discussion with PoE.

What is active PoE? If your industrial 4g router uses the PoE standard 48V 802.3af or 802.3at, it is considered to use active POE. This means that the 4g industrial router will check the power coming in, and, if it doesn’t meet the device requirements, it just won’t power up.

Then what is passive PoE? Passive PoE usually refers to any 4g industrial router using PoE that is not 802.3af or 802.3at. This includes devices such as cameras and 4g industrial router that runs on 24V or 12V 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