What is the power output of a typical PoE extender?

Power Output of a Typical PoE Extender

The power output of a PoE extender depends on the PoE standard supported by the extender, the power capabilities of the source device (PoE switch or injector), and the number of devices connected to the extender. Here's a detailed breakdown of the power output based on different PoE standards and the specific design of the extender:

1. Power Output Based on PoE Standards

IEEE 802.3af (PoE)

--- Power Output per Port: 15.4W (maximum)

--- Typical Applications: Low-power devices such as IP cameras, VoIP phones, and basic wireless access points.

PoE Extender Power Handling:

--- A PoE extender that supports the 802.3af standard will output up to 15.4W per port for connected devices.

--- The PoE extender doesn't increase the power delivered by the source (PoE switch or injector) but rather regenerates the power and data signals to extend the range, maintaining the same 15.4W output over the extended cable.

IEEE 802.3at (PoE+)

--- Power Output per Port: 25.5W (maximum)

--- Typical Applications: Moderate-power devices such as PTZ cameras, high-performance wireless access points, and LED lighting systems.

PoE Extender Power Handling:

--- 802.3at PoE extenders can support up to 25.5W per port, allowing them to deliver more power for devices with higher power requirements.

--- Like 802.3af, the extender regenerates the power and data signals from the source, but the power output is scaled up to match the capabilities of PoE+ (25.5W) devices.

IEEE 802.3bt (PoE++ / Ultra PoE)

Power Output per Port:

--- Type 3 (PoE++): 60W (maximum).

--- Type 4 (PoE++ / Ultra PoE): 100W (maximum).

--- Typical Applications: High-power devices such as advanced PTZ cameras, digital signage, industrial IoT devices, and high-performance wireless access points.

PoE Extender Power Handling:

--- PoE extenders supporting 802.3bt can deliver 60W or 100W per port depending on whether they support Type 3 or Type 4.

--- These extenders can be used to power devices with significant power demands, including large PTZ cameras with heaters, high-definition cameras, and large-scale LED lighting systems.

--- The extender will maintain these higher power levels over longer distances, assuming the source PoE switch or injector can supply the required 100W (for Type 4) or 60W (for Type 3) per port.

2. Power Output Based on Extender Design

Some PoE extenders feature multiple output ports, which means the total power available must be distributed among all connected devices. Here’s how that works:

Single-Port Extenders

Power Output: The power output is directly tied to the input power from the source PoE switch or injector. For example:

--- An 802.3af PoE extender will output 15.4W to the connected device.

--- An 802.3at PoE+ extender will output 25.5W to the connected device.

--- An 802.3bt Type 3 PoE++ extender will output 60W to the connected device.

Multi-Port Extenders

--- Power Output Distribution: In a multi-port PoE extender, the total power available from the source device is split across the connected devices. For example:

--- A 4-port PoE extender with an 802.3at (PoE+) source providing 30W could theoretically distribute 7.5W per device (assuming equal power distribution).

--- A multi-port PoE++ extender with 100W from the source could provide 25W per device if four devices are connected.

Power Considerations:

--- As more devices are connected to the extender, the available power per device will decrease. This must be taken into account when determining how many devices a multi-port extender can reliably support.

3. Key Factors Affecting Power Output

Several factors affect the effective power output of a PoE extender:

a. Source Power (PoE Injector or Switch)

--- The PoE source device (such as a PoE injector or PoE switch) must supply sufficient power to the PoE extender to meet the power requirements of both the extender itself and the connected devices.

--- For example, if the source switch supports 802.3bt Type 3, it can supply 60W per port to the extender. However, if the source switch only supports 802.3af or 802.3at, the maximum power output to the devices will be lower (i.e., 15.4W or 25.5W per port).

b. Cable Length and Quality

--- Cable length affects the power that can be effectively delivered, especially over long distances. Power loss increases with longer cables and lower-quality cables. High-quality cables (like Cat 5e or Cat 6) are essential to minimize voltage drops over extended distances.

c. Extender Efficiency

--- The efficiency of the PoE extender itself is also crucial. Some extenders may have internal power losses, meaning that not all of the input power is available for the devices. For example, if a PoE extender has an efficiency of 90%, it will lose 10% of the power during the signal regeneration process.

4. Example Power Output Scenarios

Here are a few scenarios demonstrating the power output of typical PoE extenders:

Scenario 1: Using 802.3af (PoE) Extender

--- Source Power: 15.4W from the PoE switch or injector.

--- Extender Output: 15.4W to the connected device (e.g., IP camera or VoIP phone).

--- Power Use: Low-power devices such as IP phones, 720p cameras, or simple access points.

Scenario 2: Using 802.3at (PoE+) Extender

--- Source Power: 25.5W from the PoE switch or injector.

--- Extender Output: 25.5W to the connected device (e.g., PTZ camera or high-performance WAP).

--- Power Use: Moderate-power devices that require more than 15W, such as high-definition cameras with PTZ functionality or Wi-Fi access points.

Scenario 3: Using 802.3bt (PoE++) Extender

--- Source Power: 60W (Type 3) or 100W (Type 4) from the PoE switch or injector.

--- Extender Output: 60W or 100W to the connected device, depending on the specific PoE++ standard supported.

--- Power Use: High-power devices such as advanced PTZ cameras, digital signage displays, and large wireless access points.

Conclusion

The power output of a typical PoE extender is determined by the PoE standard it supports and the available power from the source PoE switch or injector.

--- For 802.3af (PoE), the output is 15.4W per port.

--- For 802.3at (PoE+), the output is 25.5W per port.

--- For 802.3bt (PoE++), the output can be 60W (Type 3) or 100W (Type 4) per port.

The total number of devices a PoE extender can support depends on its design (single-port or multi-port) and the available power, as well as the power distribution across devices. In multi-port models, power is shared, so each device may receive less power if multiple devices are connected. Always consider the power and data requirements of your devices when selecting a PoE extender.