Power over Ethernet (PoE) is a method of providing electrical power through Ethernet cables. It is also called Power over LAN (PoL) or active Ethernet.
The PoE technology is used on the wired Ethernet and is most widely used on LANs.
PoE allows power to be transmitted to terminals through data transmission lines or idle lines. This technology provides power over a 2.5GE Base-T, 1000Base-T, 100Base-TX, or 10Base-T Ethernet network, spanning a distance of up to 200 m.
PoE system involves the following devices:
Power-sourcing Equipment (PSE)
A PSE is a PoE device that provides power to PDs and supports detection, analysis, and intelligent power management.
PD
A PD is a device that receives power from a PSE. Examples of PDs include wireless APs, portable device chargers, POS machines, and cameras. PDs are classified into standard and non-standard PDs depending on whether they conform to IEEE standards. PDs include IP Phones, Wireless LAN Access Points, IP Security Cameras and various other network devices.
PoE power supply
A PoE power supply provides power to a PoE system. The number of PDs connected to a PSE is limited by the power output of the PoE power supply. PoE power supplies are classified into built-in and external power supplies depending on whether they are swappable.
PoE Power Management Mode:
When many PDs are connected to a PSE, the PSE can no longer provide power to all the PDs and needs to manage power supply in automatic or manual mode depending on the power supply mode:
Automatic mode: The PSE automatically powers on or off PDs based on power supply priorities of interfaces.
Manual mode: You can manually power on or off PDs connected to interfaces. In manual mode, the PSE provides power to PDs without considering the priority. Po
PoE Perpetual Power Supply and Fast Power-On
Perpetual power supply protects the PDs connected to a PoE device from power failures when the PoE device restarts without being powered off using the reboot command or has the software version upgraded.
Fast power-on shortens the power failure time of the PDs when the PoE device restarts due to a power failure. This is because the PoE device continues to supply power to the PDs immediately after being powered on without waiting until it finishes restarting
PoE Technical Specifications Standards Comparison:
PoE technical specifications vary depending on PoE technologies. You can select the required PoE technology to power on PDs according to PD requirements.
PoE Key Benefits
• Installation Cost Savings
– Eliminates the need for electrical outlet installation
– Dramatically reduces the cost of deployment
– No need for bulky AC power adaptors
• Simplifies Installation
– Uses a single Cat5/5e/6 cable for both data and power
• Centralized Power Backup
– Continuous operation during power interruptions
• Centralized Power Management
– Devices can be remotely powered down during periods of low usage or for security purposes
Reference: Hedex - S300, S500, S2700, S5700, and S6700 Product Documentation
https://www.ieee.li/pdf/viewgraphs/introduction_to_poe_802.3af_802.3at.pdf
