Why We Use Power Over Ethernet (PoE)

By: Jack Vanden Broek

3 Min Read

24 Mar, 2021

We love to find solutions for our customers

A challenge that often comes up for our customers is that they would love the benefits of a SimulCharge™adapter… But their device is not located near a power outlet. Fortunately, there is a way we can solve this problem using a technology called Power over Ethernet or PoE.

Power over Ethernet to the rescue

Power over Ethernet is a standard for passing electrical power and data through a network cable. In so doing, it eliminates the need for a separate power supply and AC outlet. For reference, many products across our SimulCharge™ product families are capable of powering tablets and peripherals using this standard.

So how does it work?

Cat-5 and 6 Ethernet cables have four twisted pairs of cables within their casing. Two of those pairs are used to transmit data while the remaining two are used for power. In order for PoE to transmit that power, it must come from a central and universally compatible source. This is accomplished via a connection to Power Sourcing Equipment (PSE). This could be a power injector, or most effectively, a PoE switch — a network switch with built-in PoE capabilities. The output from the PSE can range from under 15W to 100W, depending on the power requirements of connected devices.

LAVA’s PoE Adapters

LAVA adapters are designed to come up as Class 0 devices, meaning they are limited to drawing 13.5W from the PSE. This is enough to power the adapter, enable device charging and supply power to USB peripherals.

PoE comes with perks!

PoE provides a number of advantages if applied in an appropriate context. As mentioned, only a single Cat-5 or 6 Ethernet cable is required to transmit power and data to your device. Per the PoE spec, power can be transmitted to devices located up to 328ft (100m) from the injector or switch. PoE can often be a cost effective solution because it doesn’t require an electrician to install dedicated AC power lines. Plus, most commercial and residential buildings already have Ethernet cables running through them. Finally, since no cable tethers your device to an AC outlet, PoE lets you install it where you see fit.

A PoE Case Study

In 2015, LAVA was contracted by a large Canadian retailer to help develop an in-aisle price checking system. It would require the tablet (Samsung Tab 4) to be continuously powered while maintaining a stable network connection. The use of Wi-Fi was quickly ruled out after testing: It would require costly installation of routers and further complicate any troubleshooting if the network failed.

LAVA was able to leverage its PoE adapters (nSTS and later eSTS units), the available PoE capable switches and other existing network infrastructure to create a system that could pull power and data from the network. This enabled the tablets to be charged while maintaining a stable and dedicated network connection without incurring large installation costs. Costs were kept down as no new electrical lines or outlets needed to be installed by licensed electricians. Moreover, the customer could use their own third party network installers. The added benefit of PoE was that the devices could be moved along with the aisle shelving units, if the store required re-organization.

This is just one instance where PoE was the most effective solution, but PoE can provide an efficient single cable solution to power delivery and network connectivity challenges encompassing digit signage, POS systems, and other customer facing applications.

Simple, straightforward and always thinking ahead

As with PoE, sometimes the most impactful solution is the most straightforward. At LAVA, we leverage our expertise to serve our customers, but also to educate, offer insight, and hopefully inspire by discussing past technological experiences.