PoE switch reverse power supply

Reverse PoE allows a switch to receive power from connected devices over Ethernet, eliminating the need for a dedicated AC power source.

What is Reverse PoE?

Reverse Power over Ethernet (PoE) is a technology where the power flows from the network terminal (client) to the switch, rather than the traditional direction from the switch to the device . In this setup, the switch acts as a Powered Device (PD), receiving electricity through its Ethernet ports from Power Sourcing Equipment (PSE) located at the client side. This is particularly useful in locations where providing AC power to the switch is difficult, such as corridors, basements, or outdoor installations .

How It Works

• PoE Input Ports: Reverse PoE switches have multiple input ports that can receive power from connected devices or PoE injectors .
• PoE Output Ports: Some reverse PoE switches also provide power to downstream devices like ONUs, APs, or routers via a dedicated output port, often with configurable DC voltage (commonly 5V or 12V), .
• Power Redundancy: Reverse PoE can aggregate power from multiple connections, ensuring the switch remains operational until all connected devices lose power .
• Integration with Fiber Networks: Reverse PoE switches can supply DC power to fiber devices such as ONTs, supporting flexible deployment in WISP or residential broadband networks .

Applications

• Wireless Internet Service Providers (WISPs): Enables powering outdoor switches without running AC lines, reducing installation complexity and cost .
• Urban and Rural Broadband: Facilitates network deployment in areas with limited electrical infrastructure .
• Residential and Small Operator Networks: Supports small-scale broadband setups where conventional power access is challenging .

Example Devices

• TP-Link TL-RP108GE: Features seven PoE input ports to receive power and one PoE output port to supply devices, with DC output options of 5V or 12V .
• Wanglink SG08RP: Offers PoE input on ports 1-7 and PoE output on port 8, with DC output for ONUs and APs, supporting VLAN and switch control features .

Benefits

• Eliminates the need for dedicated AC power at the switch location.
• Simplifies cabling and reduces deployment costs.
• Provides redundancy by sourcing power from multiple connected devices.
• Supports both Ethernet and fiber network devices with DC output. Reverse PoE is a practical solution for network deployments in challenging environments, enabling switches to operate reliably without conventional power sources while still powering downstream devices.