The ever-growing need for connected devices and high-performance networks has led to the deployment of billions of IoT devices globally. According to Market Watch, the number of connected devices reached 22 billion worldwide in 2018, and that number is projected to reach 38.6 billion in 2025—and 50 billion by 2030. In a recent article, Market Watch further states:

As the ecosystem evolves, so will the demands of consumers, which will increase the consumption of the Internet of Things technology for optimizing user experience across assorted devices, interfaces, and operating systems. Connected devices generate the demand for more power, light, and data coverage networks in IoT infrastructure, thereby promoting the power over ethernet solutions industry. – 2021 PoE Solutions, Market Watch

What is PoE?

Power over Ethernet (PoE) technology transmits electrical power and data over a single twisted-pair Ethernet cable to powered devices (PDs). PoE is used instead of traditional electrical wiring, which supplies power only and requires a separate cable for data. 

Because PoE transmits both power and data over a single Ethernet cable, less wiring is required for a network. Also, PoE technology can be used to power devices located in out-of-the-way places with no electrical outlets.

This fantastic technology sends 10/100/1000 megabits per second (Mbps) of data and 15 watts (W) to 100W of electrical power to network devices over Cat5e, Cat6, Cat6a, Cat7, and Cat 8 Ethernet cable for a maximum distance of 100 meters (m).

2021 PoE Terminology

Following are some standard PoE terms that are helpful to understand.

PoE, PoE+, PoE++, and Hi-PoE

PoE technology was first ratified by the Institute of Electrical and Electronics Engineers (IEEE) in 2003. Subsequent, more powerful iterations of PoE were also confirmed by the IEEE; the latest version was approved in 2018. Today, IEEE-compliant switches and injectors have an output of 12.85 watts (W) to 71W of power per port. Below is a chart that describes the four PoE standards.



PoE Types

Powered Device (PD)

Any network device powered by PoE is called a powered device, or a “PD” for short. PDs require different amounts of power. The amount of power a PD needs will determine which PoE standard you use. Here are some examples of common PDs that are powered by PoE:

PDs supported by 802.3af and 802.3at (30W or less)

  • Door Access systems
  • Computer monitors
  • IP phones
  • Laptops
  • Large computer display screens
  • Large TVs
  • Liquid crystal display screens
  • Network audio
  • Pan-tilt-zoom (PTZ) cameras
  • Remote computer terminals
  • Thin client computers
  • Video signing displays
  • Video telephones
  • VoIP phones
  • Wireless access points (WAPs)
  • WiMAX

PDs supported by 802.3bt (31W to 100W)

  • High-performance WAPs
  • Intercoms
  • Light-emitting diode (LED) lighting
  • Security card readers
  • Video conferencing
  • Video surveillance cameras

PoE Power Devices

Power Sourcing Equipment (PSE)

PSEs are the devices that power the PDs and are labeled either “endspan” or “midspan.” An endspan (also called endpoint) is typically a network switch. For example, Tech Target defines a network switch as follows:

A network switch connects devices (such as computers, printers, wireless access points) in a network to each other and allows them to “talk” by exchanging data packets. Switches can be hardware devices that manage physical networks, as well as software-based virtual devices.

A PoE switch is a Fast Ethernet (or Gigabit) network switch that has PoE integrated into it. PoE switches enable PoE-compatible PDs to work in spaces where electrical outlets do not exist.

A midspan device (typically, a PoE injector) is used when you use a non-PoE network switch to power a PoE-compatible PD. The midspan is placed between the non-PoE switch and the PoE-compatible PD, allowing the switch to power the PD. 

PoE Injector Diagram

2021 PoE Benefits

There are six main advantages to using PoE technology in your local area network (LAN).

  1. Lower Costs: Because PoE technology only requires one cable to transmit both power and data in a network, significantly less cabling is required than with traditional electrical wiring. Also, with PoE, there is no need to hire expensive electricians to install it.
  2. Quick and Easy Installation: PoE PSEs (e.g., a PoE switch or PoE injector) are simple plug-and-play devices easily installed into a network.
  3. Flexible: Using PoE technology, PDs can be located in almost any location. For example, PoE extenders can be utilized for distances longer than 100m, shielded cables can be used for outdoor equipment, and industrial-grade PoE devices can be used in harsh environments.
  4. Scalable: The plug-and-play feature of PoE devices makes it easy to add new equipment to the network.
  5. Safe: PoE uses relatively low voltages; therefore, there is minimal risk of electrical hazard.
  6. Reliable: PoE devices that are in full compliance with the IEEE 802.3 standards are dependable and sound.

PoE Benefits

2021 PoE Drawbacks

PoE is not a perfect technology. Here are four concerns that could come up:

  1. Distance: Simple PoE is limited to 100m in length. For longer distances, PoE extenders or other methods must be used.
  2. Higher switch costs: While PoE reduces overall costs by requiring the use of only one cable and easy installation without the need for an electrician, the PoE switches themselves are more expensive than regular switches.
  3. Outages: Usually, a single PoE connection links multiple devices. One failure in the stream of devices brings all devices down.
  4. Power Limits: The maximum amount of power supplied by PoE technology is 100W.

Last Thoughts

Power over Ethernet is a technology that has proven to be both a time and cost savings. PoE can be easily added to your network, and it is suitable for a wide variety of applications. If you are considering an upgrade of your business network, consider implementing PoE-capable switches.

Planet Technology USA is a proud distributor of PoE switches, injectors, extenders, and more. Visit our homepage by clicking here.