Power over Ethernet (PoE): Benefits & Uses

 An Overview of Power over Ethernet (PoE)

 What is PoE?

Power over Ethernet (PoE) is a technology that simplifies network systems by delivering both data and electrical power over a single Ethernet cable. It eliminates the need for separate power supplies, thus helping to streamline installation and reduce clutter. With this, PoE offers more flexibility than traditional power setups, making it ideal for connecting IP cameras, wireless access points, and other devices, especially in areas that lack power outlets.

The 4 Main PoE Types

There are four types of PoE equipment, each defined by the IEEE (Institute of Electrical and Electronics Engineers), an international organization that focuses on setting industry standards for technology safety and compatibility. These four types of PoE equipment have varying output levels. However, it is important to note that cable distance can cause some power loss, so the actual power received by the device might be slightly lower than the maximum output of the PoE source.

Type 1 (802.3af Standard)

Simply known as “PoE'', the original Type 1 standard was first introduced by the IEEE in 2003. It uses two wire pairs in the Ethernet cable for power delivery and the other two for data transmission, delivering up to 15.4W (watts) of power, leaving around 12.95W for the powered devices.

Type 2 (IEEE 802.3at Standard)

Type 2 PoE+, came out in 2009 with a significantly boosted power output of 30W, whereas the power received by the connected devices is typically 25.5W. Just like Type 1, it uses two pairs of wire respectively for transmission of power and data in the Ethernet cable.

Type 3 (IEEE 802.3bt Standard)

Type 3 PoE++ can also be referred to as 4PPoE (Four-Pair Power over Ethernet) or Ultra PoE. It was standardized in 2018 and utilizes all four pairs in the Ethernet cable for power and data delivery, increasing power levels to 60W, while the connected devices receive up to 51W.

Type 4 (IEEE 802.3bt Standard)

Type 4 PoE++ was released alongside the Type 3 version in 2018. Similarly, it has the common name of 4PPoE, and it also leverages all four pairs in the Ethernet cable for transmission, but it boasts an even higher maximum output level, up to 100W, with the connected devices receiving around 71.3W after cable dissipation.

How Does Power over Ethernet Work?

To operate properly, Power over Ethernet relies on two crucial components: the power sourcing equipment (PSE) and the powered device (PD). The PSE acts as a power source, integrating electrical power with data before transmitting them into the network system, whereas the specific amount of power it can deliver depends on the PoE standard we mentioned earlier. On the other hand, PD refers to any devices that leverage PoE technology to receive both power and data through the same Ethernet cable. 

Moreover, there are two ways a PSE can supply power, either through an endspan (Mode A) configuration with PoE switches or a midspan (Mode B) configuration with PoE injectors. We'll delve deeper into the differences of these approaches below.

Transmission with a PoE Switch (Endspan)

The method using a PoE switch is also known as Mode A or endspan configuration. PoE switches have built-in power sources and data switching capabilities, so they can be connected directly to the PoE powered devices with an Ethernet cable.

Transmission with a Poe Injector (Midspan)

PoE injectors are used when there is a non-PoE switch in the system, creating a Mode B or midspan configuration. They will be connected in between the non-PoE switch and PoE devices, acting as an alternative power source that will inject electrical power into the data stream before it reaches the PD. This way, anyone can leverage the benefits of Power over Ethernet within an existing network infrastructure.

What is PoE Used For?

Common Applications of PoE

PoE can be used to provide power and data for network devices in various locations, even when electrical circuitry is not readily available. Here are some of its common applications:

• Security Systems: PoE can be used to power IP cameras and access control systems. This allows flexible and strategic placement of security devices, enhancing the security coverage in facilities with limited power sources. 
• Voice over Internet Protocol (VoIP): By reducing reliance on nearby power outlets, PoE enables deployment of VoIP phones in remote areas, facilitating steady voice communication across the network.  
• Wireless Access Points: PoE can help extend Wi-Fi coverage, especially in locations where installing new power lines might be difficult or expensive, ensuring seamless connection throughout the facility. 
• Building Automation: PoE simplifies the installation of smart building devices, such as contact detectors, humidity sensors, alarm control systems, etc, no matter the amount of electrical outlets available on site. 
• Retail Displays: PoE can supply power for digital signage and interactive kiosks, eliminating the need for separate power supplies, thus reducing cable clutter and creating a cleaner aesthetic in retail environments. 
• Manufacturing Execution System (MES): In manufacturing, PoE can power devices that monitor and control production processes, such as Advantech's HMI Terminal, streamlining data collection on the factory floor. 
• Factory Automation: Factories can deploy devices like Advantech’s PoE sensing gateways to seamlessly integrate various sensors and devices in the production line, boosting the overall efficiency of operations with centralized power management.  
• Intelligent Transportation System (ITS): PoE can offer a reliable data communication network for ITS devices, like traffic monitoring cameras or rail communication systems, even if power sources are limited in the area. However, it is important to use PoE switches that can withstand shock and vibration, such as Advantech's EN 50155 model, to ensure smooth operation in these applications.

Compatibility of PoE Standards for Various Applications

Similar to common electronic devices, each PoE-powered device consumes different amounts of power. Therefore, users have to select a PSE with the right wattage depending on the power requirements of the specific PD. This is crucial for reducing the risk of malfunctions or inefficient power/data delivery.  

For your reference, we’ve summarized the features of each PoE type and provided some examples of suitable applications in this table:

As mentioned above, this table is for reference only. If you are unsure about the compatibility or power requirements of your PoE systems, always refer to the product’s datasheet or contact your device manufacturer for more information.

Benefits and Limitations of Power over Ethernet

Power over Ethernet offers lots of advantages for the network infrastructure but also has some limitations that need to be understood for optimal performance. So, we’ll delve deeper into the benefits and considerations of utilizing PoE in this section.

Benefits of PoE

Streamlined Installation

PoE simplifies the installation process of network systems by eliminating the need for nearby outlets and multiple cables, as it only requires a single Ethernet cable for transmitting data and power. This also translates to faster deployment times and reduced labor costs.

Cost Effective

Although implementing PoE for older systems may require a higher initial cost, it can save resources in the long run. On top of reducing installation fees, PoE can also lower energy consumption due to its efficient power delivery, allowing cost savings in energy bills.

Higher Versatility

Since PoE only requires an Ethernet port, users can have more flexibility when positioning their devices, allowing them to optimize network coverage and device functionalities without the restriction of power outlets. PoE technology is also highly scalable, making it easy to adapt infrastructures for future needs.

Increased Network Reliability

PoE systems are known for their stability, as they have to adhere to the strict regulations of the IEEE to be officially certified. In turn, this offers consistent power delivery and minimizes the risk of outages, ensuring reliable network connection and smooth operation.

Centralized Power Management

PoE power supplies will act as a central hub, providing consistent and manageable power distribution to the PDs. Not only can this simplify power delivery, but it also enables power monitoring and troubleshooting, allowing users to have a proactive approach for system maintenance.

Limitations of PoE

Limited Operation Distance

PoE equipment can effectively operate up to a distance of 100 meters (328 feet). Beyond this distance, cable resistance increases, so the PDs might not receive enough power to function properly.

Fortunately, PoE extenders offer a solution to increase PoE's reach, breaking the transmission distance limit beyond 100 meters. It will receive the PoE signal from the PSE via an Ethernet cable, amplify both the power and data, then transmit this amplified signal to another Ethernet cable, allowing it to power devices that are further away.

Nevertheless, it's important to note that PoE extenders may introduce some additional power loss, due to the amplification process. Hence, careful planning is necessary to ensure sufficient power delivery for the devices, even with extenders.

Additional Hardware for non-PoE Equipment

Not all equipment has built-in PoE capabilities, especially if they are older models or low-power devices. To integrate this equipment into a PoE network, users may require additional hardware, such as PoE injectors or PoE media converters.  

PoE media converters can inject power into a data transmission, just like PoE injectors. At the same time, it will convert the signal format between copper and fiber optic cables, eliminating the need to replace existing copper cable infrastructures.

Although PoE injectors and media converters can bridge the gap for non-PoE devices, the additional hardware may be a drawback for space-constrained environments.

Power over Ethernet FAQs

What is the Difference between PoE-Compatible Devices and PoE-Compliant Devices?

PoE-compliant devices have an official IEEE certification, ensuring reliable and predictable performance within a PoE network; PoE-compatible devices don’t necessarily meet IEEE standards but usually function properly in a PoE network.  

PoE-compliant PDs have undergone rigorous testing to guarantee they meet specific criteria for power delivery and data transmission in both endspan and midspan configurations; whereas the regulations for PoE-compliant PSEs are slightly more flexible, so they might only support one of these configurations. 

Conversely, PoE-compatible devices are considered a budget-friendly option, but their power delivery and data transmission capabilities are inconsistent, differing from manufacturer to manufacturer. To avoid network disruption or equipment damage, it’s always best to consult the manufacturer's specifications and ensure compatibility before integrating these devices into the PoE network.

What Kind of Ethernet Cables Should be Used for PoE?

Not all Ethernet cables support PoE, as it demands faster data rates or longer cable runs compared to typical network systems. To ensure safety and reliability, it is strongly recommended to select cables meeting at least Cat5e standards. These cables offer thicker conductors better suited for PoE applications. Cat6 or higher cables are also excellent choices, providing increased bandwidth and better resistance to electrical interference.  

On the other hand, Cat3 cables or lower should be avoided as their thin conductors can't handle the higher currents associated with PoE. This can lead to power loss, performance issues, or even overheating which can potentially damage the cable and connected devices.

Is PoE Safe? Will it Cause Damage to Devices?

PoE compliant with IEEE 802.3 af/at/bt standards are indeed safe and normally will not cause damage to the connected devices. Unlike traditional power outlets with constant voltage, compliant Power over Ethernet PSE will initiate a handshake process with PD before supplying power, releasing a low voltage signal to identify the PD’s power requirements. Then, the PSE will only deliver the necessary amount of power to ensure safe operation. If the handshake fails, the PSE will completely withhold power delivery, preventing accidental damage or activation of the device.  

Furthermore, PoE operates within the Safety Extra Low Voltage (SELV) standard as defined by the International Electrotechnical Commission (IEC). This means the typical PoE voltage range (35V to 57V) poses minimal risk of electrical shock under normal operating conditions.  

However, while the handshake and low voltage minimize risk, improper use or cable degradation can still cause electrical hazards. So, it is important to avoid overloading the PoE system and conduct regular inspections of cables to ensure their integrity.

How to Integrate Non-PoE Devices to a PoE Network?

Non-PoE devices can be integrated into a PoE network with the use of PoE splitters. The PoE splitter will receive the combined data and power signal from the PSE through a standard Ethernet cable. Then, it will split the signal into two outputs: the data output and the power output. With this, the non-PoE device can function just like a PoE device. 

What is the Lifespan of a PoE Switch?

The average lifespan of a PoE switch can range from 3 to 10 years, depending on usage and hardware quality. Though they have a higher initial cost, high-quality PoE switches from trusted brands are worth the investment, as they tend to last longer. This will reduce downtime and save money in the long run.

Advantech Power over Ethernet Device Solutions

While the demand for efficient power delivery and integrated systems grows, Power over Ethernet will continue to play a crucial role in the advancement of network infrastructures across various industries. This technology doesn’t just simplify installation, it can offer cost savings, improved flexibility, and increased reliability in a network system 

 As a leading provider of high-quality networking solutions, Advantech offers a comprehensive range of PoE products to meet your diverse needs. Our catalog includes everything from efficient PoE switches, PoE injectors, PoE media converters, to PoE splitters for connecting non-PoE devices, and even PoE extenders for overcoming distance limitations. Unlock the full potential of your network with Advantech today!