Passive PoE (Power over Ethernet) and 802.3af are two different standards for delivering power over Ethernet cables to network devices.
The main difference between passive PoE and 802.3af is the method used to deliver power to the device.
Passive PoE delivers power over Ethernet using a simple pair of wires, while 802.3af uses a more complex method that involves negotiating power requirements between the power source and the device being powered.
Passive PoE is a simpler and less expensive technology, but it has some limitations. It does not support the same range of power levels as 802.3af, and it does not include any safety features to protect against damage caused by incorrect wiring or overloading.
In contrast, 802.3af is a more advanced and standardized technology that is widely used in modern networks. It includes features such as power negotiation, power management, and safety mechanisms to protect devices from damage. 802.3af also supports a wider range of power levels and can power a broader range of devices.
Overall, while passive PoE is a simpler and less expensive option, it may not provide the same level of functionality and safety as 802.3af. 802.3af is a more advanced and standardized technology that offers a wider range of features and capabilities for powering network devices.
Passive PoE is typically used with low-power devices that have a fixed power requirement, such as outdoor access points, wireless bridges, and IP cameras. These devices are designed to work with a specific voltage and current, and passive PoE delivers power to them without the need for any power negotiation or management.
Some access points that support passive PoE include Ubiquiti Networks UniFi UAP-AC-M, Mikrotik hAP ac lite, and TP-Link CPE510. It is important to check the specifications of your access point to ensure that it supports passive PoE before purchasing a passive PoE injector or switch to power it.
It is also important to note that passive PoE injectors and switches should be used with caution, as they do not include the safety features found in 802.3af or other standardized PoE technologies. Overloading or miswiring a passive PoE device can cause damage to the device or create a safety hazard, so it is important to follow proper installation procedures and use reliable equipment.
Here are some of the most common types of PoE injectors:
Single-port PoE injector: This type of PoE injector is designed to provide power to a single PoE-enabled device, such as a wireless access point, IP camera, or VoIP phone.
Multi-port PoE injector: This type of PoE injector is designed to provide power to multiple PoE-enabled devices simultaneously, such as several wireless access points or IP cameras.
Passive PoE injector: This type of PoE injector delivers power to PoE-enabled devices without any negotiation with the device. Passive PoE injectors are typically used with non-standard PoE devices that do not support the IEEE 802.3af/at standards.
Active PoE injector: This type of PoE injector negotiates with the PoE-enabled device to determine the amount of power it needs. Active PoE injectors are typically used with standard PoE devices that support the IEEE 802.3af/at standards.
Gigabit PoE injector: This type of PoE injector is designed to deliver power and data over a single Ethernet cable to high-speed Gigabit PoE-enabled devices, such as IP cameras and wireless access points.
Outdoor PoE injector: This type of PoE injector is designed to be used in outdoor environments, where the device must be weatherproof and able to withstand extreme temperatures.
Rack-mount PoE injector: This type of PoE injector is designed to be mounted in a network rack and can supply power to multiple PoE-enabled devices simultaneously.
Overall, PoE injectors are useful devices that can simplify the installation and management of PoE-enabled devices by delivering power and data over a single Ethernet cable. The choice of PoE injector depends on the specific use case and the number and type of PoE-enabled devices that need to be powered.