What is Power over Ethernet (PoE)?

July 17, 2023 - Power over Ethernet (PoE) is a technology that transmits electrical power through an Ethernet cable. PoE works by injecting direct current (DC) power into the cable which is accessed by the powered device (PD) through a PoE-enabled network switch or PoE Injector. These PoE switchers and injectors are commonly referred to as PSE (Power Source Equipment). In many PoE devices, this system also allows the device to access both data and power. 

What is Ethernet?  

Ethernet is the terminology for a wired local area network (LAN) which provides the means of connecting computers and other devices to data communication. In an Ethernet network, data is transmitted through packets known as Ethernet frames, typically via twisted-pair copper cables which connect the devices and transmit data.   

What devices use PoE?  

Historically, PoE has primarily powered devices like cameras, intercom systems, wireless access points, and IP phones. This is because PoE has, until recently, been designed for low-to-moderate power devices. Newer PoE standards such as IEEE 802.3bt-2018 (also known as PoE++ or 4PPoE) deliver up to 70 watts or more to PDs, greatly widening the possible scope of PoE applications. 

With GPO Displays’ new line of PoE Panoramic LCDs, it is now possible to power larger display devices with screen sizes ranging from 27” to 50” (diagonal). This represents the first complete lineup of large-format stretched-aspect ratio LCDs ever. AC outlets are commonplace in areas where more traditional displays are wall-mounted, such as focal points of conference rooms or large walls in lobbies. However, they are rarely found above & alongside doorways, where Panoramic LCDs are often used as room status signage. This is just one example of why PoE is uniquely beneficial for Panoramic displays in particular. 

What are the benefits of PoE?

• Scalability: Once a PoE system is set up, it is very scalable. Existing cables can be used to expand the network and add more displays or create a larger system.  
• Reliability: While AC outlets are a set of distributed wall adapters, PoE comes from a central source and can be backed up but a UPS (uninterruptible power supply) to ensure continuous operation in mission-critical environments. 
• Safety: When connections are interrupted, PSEs typically have an automatic cutoff feature and stop delivering power. A handshaking process must be established before power is transmitted again. 
• Cost & Convenience: Even in cases where there is limited or no existing cabling infrastructure, it may still be the most cost-effective option. Anyone can lay Ethernet cables, whereas installing an AC outlet (used for non-PoE devices) requires an electrician. This can be costly, time-consuming, and a scheduling nightmare.   
• Flexibility: Devices such as PoE Panoramic LCDs no longer need to be tied to AC outlets. PoE gives you the flexibility to add displays in unique & creative applications, and in locations you never thought possible. 

Overall, PoE can save time and money while enabling easy and innovative deployment of digital signage in a wide range of environments.  

By Sareesha Nile