Power Over Ethernet: Fully Explained and Revised for 2019 (Updated)

What is Power Over Ethernet (PoE) and what is it used for?

Power over Ethernet (POE) is a networking feature that lets network cables carry electrical power over an existing data connection with a single Cat5e/Cat6 ethernet cable.

PoE technology relies on the IEEE 802.3af and 802.3at standards, which are set by the Institute of Electrical and Electronics Engineers and govern how networking equipment should operate in order to promote interoperability between devices.

>>Download the full infographic right here<<

PoE-capable devices can be power sourcing equipment (PSE), powered devices (PDs), or sometimes both. The device that transmits power is a PSE, while the device that is powered is a PD. Most PSEs are either network switches or PoE injectors intended for use with non-PoE switches.

Common examples of PDs include VoIP phones, wireless access points, and IP cameras.

What is the advantage of PoE?

Power over Ethernet (PoE) allows for installation of remote or outside equipment without having to connect to AC power. This allows power to be delivered to more areas without the need to install additional electrical infrastructure or to have power outlets at every endpoint. Equipment can be installed without the need for an electrician and because ethernet cable costs less and is often already installed in buildings, PoE-based systems are far more cost-effective and efficient.

What are the benefits of PoE?

PoE benefits organizations in 5 primary ways—reduced installation costs, installation safety, responsive deployments, data-gathering capabilities, and productivity enhancements. End users can plug PoE capable devices into existing networks or start from scratch with ease.

Here’s an explanation of the list above:

1. Why does PoE reduces installation costs?

PoE installation costs are far less than the cost of installing traditional wiring, and the operating costs are far more efficient. One twisted pair cable delivers both data and power to devices. Existing copper from legacy phone systems can also be repurposed.

2. Why is PoE Installation safer?

PoE Type 3 voltages are typically less than 60 volts, and Type 4 less than 90. Conduits and metal cladding are not required. Fewer steps and hazards and the straightforward use of one Cat5e or Cat6 Ethernet cable, remove the need for a licensed electrician.

3. Why are PoE deployments more responsive?

PoE devices adapt to changing environments. They can be easily moved and reconnected at the switch level and easily integrate into changing network configurations. PoE is plug and play. An entire network does not need to be brought-down to add or subtract devices.

4. What are PoE data-gathering capabilities?

PoE technology is perfect for data collection. For example, analytics software can help facilities groups to determine when an area is occupied and when LED lighting and HVAC components may be turned off. Operational costs can be much lower based on actual usage.

5. Why PoE enhances productivity?

LED lighting systems, because of 2-way data capabilities, can be programmed to follow spectrum and frequencies found in nature. Employees can enjoy greater health, alertness, creativity, collaborative opportunities, and a sense of well-being while on the job.

All of these features allow organizations the ability to control and limit costs without sacrificing quality of life.

What are some limitations of PoE?

The limitations of PoE are few but should be taken into account when adopting for the first time: 1.) Simple PoE only transmits signals 100m; 2.) Non-compliant devices require additional equipment; 3.) Power budgets may only achieve levels available on legacy equipment.

This section will further expand these 3 limitations and how to adjust for them:

  • Transmission distance
  • Device compatibility workarounds
  • Power delivery rates

PoE LimitationsWhat is the maximum distance of PoE?

PoE can transmit 100 meters from the switch or hub to the NIC, regardless of where the power is injected. The limitation is not the power; it’s the Ethernet cabling standards that limit the total length of cabling to 100 meters. The furthest distance a PoE switch can transmit simple data over Ethernet is a distance of 100 meters. A PoE Ethernet Extender, however, can lengthen that span up to 4000 feet.

For networks spanning enterprises, campuses, and large retail operations like shopping malls, extended reach allows centralized control across a wide area.

What does device compatibility refer to?

Legacy devices, those that are not PoE compliant, require either an injector or a splitter. PoE delivers power AND data over one cable and therefore one input. Legacy devices receive data and power separately.

  • A PoE Injector sends power to PoE equipment that receives data through existing non-POE switch.
  • A PoE Splitter also supplies power, but it does so by splitting the power from the data and feeding it to a separate input that a non-PoE compliant device can use.

How much power can PoE deliver per port?

When purchasing, administrators want to be sure the maximum power budget of a switch is sufficient for the devices it supports. Identify the manufacturer power spec/budget per port to know if the end device will receive required power through that switch. Find these levels expanded in the next section.

Free PoE CalculatorHow much power can PoE devices supply?

PoE devices supply power according to the device IEEE 802.3 generation. The life-cycle generation is indicated by the extension: “af,” “at” or PoE+, and “bt” or “UPoE”. The following chart provides side-by-side comparison of maximum power each PoE Type delivers at the port level.

IEEE Standards and DevicesWhat devices use PoE?

The devices using PoE to receive data and power known are smart technologies, those found in the Internet of Things (IoT). A list of examples follows. Keep in mind this list keeps expanding as more people adopt PoE and manufacturers continue to prioritize development of these products.


  • PoS Kiosks
  • Security Access Controls
  • Industrial Controls
  • Digital Signage
  • Smart Clocks
  • Routers
  • Wireless Access Points
  • IP/Pan-Tilt-Zoom Cameras
  • VoIP Phones


What is PoE+?

Power over Ethernet Plus (PoE+) is the 2009 Ethernet standard amendment released by the Institute of Electrical and Electronic Engineers, also known as (IEEE) 802.3at. PoE+ delivers 30W at the port level over an Ethernet twisted pair cable.

PoE vs. PoE+

The original PoE IEEE 802.3af, completed in 2003, delivers 15.4W. Never ratified, this version was more-or-less an informal working version of its successor, the 802.3at. The big difference is 802.3at delivers more power per device.

Can I mix PoE and non-PoE devices in my network?

PoE and non-PoE devices can mix in the same network. Non-PoE devices require a separate power source. A PoE splitter may also be required if the device does not support PoE. This will split power and data from the PSE.

Which Versa switches are PoE-capable?

Versa PoE Switch

The Versa switches that are PoE capable may be found on our PoE page. In the left hand column, they are also listed by number of ports. Look for “tipoff” acronyms clearly marked on the external chassis of the switch.

DMS Device management systems

UPOE Ultra power over ethernet

Gbe    gigabit ethernet

PoE    power over ethernet

Power Over Ethernet Applications

PoE applications power an increasing percentage of 8.4 Billion IoT connected devices, that number is up 31% from the previous year. Higher-powered IEEE 802.3bt supports: thin client computers, VoIP phones and wireless networks, IP security cameras, facility monitoring controls, digital signage, point of sales kiosks, and LED lighting & sensors.

What is PoE lighting?

PoE lighting is a low power, high performance LED lighting network technology comprised of fixtures and sensors, and is managed remotely using intelligent software. The control module communicates data signals and power over twisted pair cable.

PoE LightingWhat are PoE lighting systems?

PoE lighting systems are networks consisting of PoE switches, lighting controls, sensors, and LEDs connected to LANs over twisted pair cables. Lighting controls allow end users to mirror the features of daylight to promote health, productivity, and collaboration using a broad spectrum of visual frequencies.

Data may be collected from motion sensors, allowing organizations to better monitor and control energy consumption. Individuals and organizations are leveraging these benefits in homes, work environments, academic and hospitality settings, and especially in medical treatment facilities.

PoE Smart Home

What are PoE smart homes

PoE smart homes are connected homes providing optimal living with centralized management capabilities for lighting, temperature, energy, home entertainment, IP security, and other devices such as appliances and door locks. Intelligent controls allow homeowners remote monitoring access via phone or tablet.

  • Smart home technology facilitates green living through energy economy.
  • Smart homes repurpose the existing copper found in apartment building telecoms cabinets, cutting down the carbon footprint.
  • Smart homes promote health and well-being through strategic placement of LED lighting and sensors.
  • Smart homes connect family members through efficient communication systems such as virtual assistants.

Commercial PoE Applications

PoE Commercial Applications

PoE smart technologies pave the way for better lighting and energy economy by turning off climate and lighting systems on unoccupied floors. Automated access points limit access to rooms, floors, and facilities 24/7 through use of retinal scanners. Other applications like Wi-Fi and room sensors reduce stress for busy IT administrators.

  • PoE connected LED products will allow consumers to glean from enormous amounts of data and develop performance enhancements, energy savings standards, and redirect saved revenues to other parts of business.
  • Digital signage on the sides of buildings, in busy airports, or sporting venues can be installed over a distance of up to 34K feet, using an Ethernet extender, and powered through a single cable without a local power source.
  • Fast improving PoE-connected wireless access technologies will keep pace with wired infrastructure when replacement becomes necessary. Copper wire can last 100 years or more, but insulation deteriorates sooner.
  • Well placed security access points and IP security cameras, especially in remote areas, allow businesses to guard secure areas and intellectual properties.

Industrial PoE ApplicationsPoE Industrial Applications

Industrial PoE applications help developers stay competitive. Sensors and IP cameras allow managers to observe manufacturing floors to monitor automated equipment and employee behaviors. This watchdog capability is an essential to lean manufacturing development. PoE also facilitates large data transfer and power distribution to key areas.

  • Safety compliance can be better documented eliminating accidents in work areas.
  • Sensors help monitor accuracy along assembly lines and eliminate waste.
  • Loading docks, inventory rooms, and other key areas, even those without a local power source,  can be tracked and improved using footage capturing employee transitions and down times.
  • Sensors can track things not visible to the eye such as temperature changes, protecting products at vulnerable stages of development.

What is a PoE switch?

A PoE switch is a network switch with the ability to provide power over Ethernet from each interface while still being able to forward frames. Both managed and unmanaged PoE switches are available. A PoE switch requires one Uplink to an existing network to further expand and increase ports.

PoE Switch Application

What is a PoE Hub?

A PoE hub can be viewed as a stack of PoE injectors. Example, a 4 port PoE hub will have 4 data-in interfaces and 4 PoE interfaces. Each PoE interface requires a data connection with the corresponding data-in side. A 4 port PoE hub will require 4 data ports from your network switch. Data ports on the PoE hub will not forward frames within the hub (frames received on port 1 cannot be forwarded to ports 2-4).

PoE Hub Application

What is a PoE splitter?

A PoE splitter supplies power to non PoE compatible devices by splitting power from data and feeding it to a separate input. Splitters are used on legacy and low power devices like IP cameras, to split PoE power from data signal, and convert to lower voltage requirements for the camera.

PoE Splitter Application

What is a PoE injector?

A PoE injector is a device that sends power to signals sent from a non-compatible PoE switch to PoE equipment. Though current switch purchases tend to be of PoE compatible models, PoE injectors are required in situations where existing equipment is older and will be cycled out at a future date.

PoE Injector Application

What is a PoE extender?

A PoE extender is a device used to extend Ethernet network devices beyond the basic 100m distance limit for twisted pair Ethernet cable. Extenders unite networks that span large distances in settings such as, hotels, shopping malls, business and academic campuses, and sporting venues.

PoE Extender Application

Future Developments in PoE

  1. Labeling of PoE equipment – the big one is still propagating through the NFPA for the 2020 NEC, and will be most of the year.  That one will be newsworthy when the first draft of the 2020NEC is published around June.
  2. Related to labeling PoE equipment – the Ethernet Alliance PoE logo program.  Recently announced, and underway for ‘generation 1’ (802.3af and 802.3at PoE), and soon to be started for ‘generation 2’ which is the new 802.3bt Type 3 and Type 4 PoE.  Gen1 is news now, Gen2 should be news before June, but not quite yet.

best poe adapters

NOTICE: We will continue processing orders as usual despite the COVID-19 situation until further notice.