Simplifying Connectivity with Power over Ethernet

The Business Benefits of Robustel PoE Solutions

White Paper – Executive Summary

Brief

Power over Ethernet (PoE) has transformed how connected devices are deployed by delivering both power and data over a single cable. From IP cameras and access points to industrial IoT gateways, PoE reduces installation costs, accelerates rollouts, and allows devices to be placed exactly where they’re needed — even in hard-to-reach locations .

Robustel’s PoE-enabled routers, such as the R2120, combine the functions of a managed PoE switch and 4G router in one device. This reduces points of failure, simplifies deployments, and adds remote management capabilities. Features like per-port power control, diagnostics, and remote reboot deliver powerful operational benefits, cutting the need for costly site visits and boosting uptime .

By integrating PoE across its router portfolio, Robustel enables businesses to unlock new value: powering non-PoE devices with splitters, optimizing router placement for signal quality, supporting in-vehicle installations, and improving overall network resilience with UPS-backed PoE infrastructure .

What you’ll learn
  • The fundamentals of PoE technology and the difference between PSE (Power Sourcing Equipment) and PD (Powered Devices).
  • How PoE simplifies deployments for VoIP phones, Wi-Fi APs, IP cameras, and industrial IoT gateways.
  • The business case for PoE: lower installation costs, fewer failure points, and faster rollouts.
  • How the R2120 acts as both router and PoE switch, with per-port control, diagnostics, and remote reboot capability.
  • How PoE splitters can extend functionality to non-PoE devices, broadening deployment options.
  • Practical use cases including signal-optimized router placement, in-vehicle deployments, and UPS-integrated reliability.

Introduction

Power over Ethernet, commonly abbreviated to ‘PoE’, is a simple concept that describes how to deliver both power and data to an electronic device over the same piece of (typically) CAT 5 or CAT 6 cable. Its origins are in consumer electronics where the ease of installation and convenience of not having to have many
additional power supplies around a building are a very obvious benefit.

Traditionally, POE has been used to connect the following devices:

  • VoIP handsets: One less PSU is required if power supplied over data cable
  • WiFi Access Points: for optimal radio coverage, siting of APs can be in hard to access places. PoE means that only having to get one cable to the AP can save significant time and cabling cost
  • IP Cameras: Cameras are often located in difficult to reach places as they need an optimal field of view to perform their primary purpose. This is another perfect example of POE reducing cost.

Types of PoE Devices

It is important for users to be clear on the two fundamental types of POE device. A device that provides power is known as PSE (Power Sourcing Equipment)
A device that uses / consumes power is a PD (Powered Device)

More detailed descriptions below:

Power Sourcing Equipment (PSE)

“Power sourcing equipment” (PSE) are devices that provide (source) power on the Ethernet cable. This device may be a network switch, commonly called an
endspan (IEEE 802.3af refers to it as endpoint), or an intermediary device between a non-PoE-capable switch and a PoE device, an external PoE injector, called a midspan device.

Powered Device (PD)

A “Powered device” (PD) is any device powered by PoE, thus consuming energy. Exam- ples include wireless access points, VoIP phones, and IP cameras.

As the PoE standard has evolved, the power delivery capability has evolved with it. The table below highlights the different standards available.

Property

802.3af

802.3at

802.3bt Type 3

802.3bt Type 4

Power Available at PD

12.95W

25.50W

51W

71W

Power Supplied by PSE

15.40W

30W

60W

100W

It is important to note that at the time of writing Robustel only has products with 802.3af or 802.3at capability as the majority of applications can be handled by the minimum 25W that 802.3at makes available to the end device.

PSE Solutions

R2120

The R2120 is Robustel’s primary PSE capable device that can be used as a 4G router as well as providing power to attached devices.

This product operates effectively as a managed POE switch + router in one product. This means less points of failure than a 2-product solution and a simpler / smaller footprint physical installation.

R2120’s four fast Ethernet LAN ports support POE feature (Voltage range: 48 to 57 VDC), which can electrify the network terminal devices such as IP camera and other WLAN AP etc.

The screenshot below shows the corresponding page in the router’s menu system. Not only is the power status (on/off) made available to the user but also the voltage and current allowing basic diagnostics to be carried out and also power consumption calculations to make sure the most cost-effective 48 VDC PSU is selected for the application.

The ability to switch POE on/off on a per port basis effectively gives a ‘remote reboot’ capability for all attached devices. This remote reboot capability from the R2120 can potentially save the cost of a site visit just to power cycle a POE powered device that has ‘locked up’ & this is where the business case for POE attached devices can be very strong.

Robustel are frequently asked what the options are for remotely raising / lowering the POE power to an Ethernet port on the R2120 router.

These are as follows:

  1. Use a fixed IP SIM to remotely access the router GUI and change the status through the HTTP(S) browser interface
  2. Use a fixed IP SIM to remotely access the Command Line Interface (using SSH or Telnet) and issue text commands to change configuration status
  3. Use RCMS (Robustel’s cloud management platform) to easily access the Command Line Interface of the R2120 and issue text commands to change configuration status (Does not require fixed IP SIM!)
  4. Embed the Command Line Interface commands into the payload of an SMS message sent to the telephone number of the SIM in the router. Sender whitelist and User/Password authentication provide the security to make this a very plausible & flexible “out of band” solution.

Using a PoE Splitter for Added Value & Innovation

An important logical extension of the above ‘remote reboot’ capability is that non-POE devices can also be powered by the R2120 with the use of a ‘POE splitter’.

A splitter is able to “split” the Data and Power connections back into their component parts and is able to provide a solution for remote powering of non-PoE devices.

Below is a list of devices that ‘could’ be run from the power supplied by an 802.3at standard POE splitter:

  • Raspberry Pi
  • RS232 / RS485 to Ethernet converter
  • Other Single Board Computer

PD Solutions

A large portion of the Robustel product portfolio either offers PoE-PD by default or as an optional extra depending on the SKU.

Below are the key reasons why you might select a POE-PD model from Robustel’s portfolio:

Optimal sitting of Router for 3G/4G signal strength

Plant rooms are often located in the basement / cellar of buildings, places where traditionally it can be hard to receive a cellular network signal. Even the use of roaming (multi-network) SIMs might not solve the problem so the only solution may be to physically locate the router elsewhere. In this instance the 100m cable run that POE allows can be used to good effect to easily change the location of the router without having to route power and data separately. There may even be existing CAT5/6 infrastructure that can be used for this purpose.

In-Vehicle Installations

Some buses and commercial vehicles already have powered Ethernet infrastructure to make installation of IP Cameras easy. This can also be leveraged to make 4G
router installation easy and provide flexibility as to where they can be installed in a space-constrained vehicle.

Reliability

If a UPS is used to hold up the power to a POE enabled switch, then the PDs connected to that switch will also benefit from the security provided by the UPS (Uninterruptible Power Supply). The router can also be appropriately connected to be aware of power loss to the UPS (typically a Digital Input or RS232 connection) and send a warning that power has been lost to the UPS and shutdown in x minutes is pending.

Partner with Robustel: Connectivity Anywhere


Simpler installations. Lower costs. Smarter deployments. Robustel’s PoE solutions deliver more than power — they deliver business value by making IoT networks easier to install, manage, and scale. Partner with Robustel today to unlock the benefits of PoE in your next project and build connectivity solutions that are more reliable, flexible, and future-ready.