Demystifying IEEE 802.3bt: When Do You Need It?

Posted on May 22, 2024 by

Networking technology is constantly advancing, meeting the need for more power and efficient data communication. Power over Ethernet (PoE) technology is a key part of these advancements. The new IEEE 802.3bt standard marks a groundbreaking development important for business owners, IT professionals, and tech enthusiasts. This article explains IEEE 802.3bt and offers tips on upgrading your network infrastructure smoothly.

What Is IEEE 802.3bt PoE Standard?

802.3bt is an enhancement to the existing IEEE 802.3 Ethernet standard, introducing significant advancements in PoE technology. Before 802.3bt, PoE devices like IP cameras and VoIP phones could transmit power and data through a single Ethernet cable. They do not require additional power sources. 802.3bt, often referred to as PoE++, builds upon these capabilities by significantly increasing the amount of power that can be transmitted, reaching up to 90 watts over a standard Ethernet cable.

Distinguishing IEEE 802.3bt from IEEE 802.3af/at

The key distinctions lie in the power delivery capabilities, efficiency, and supported applications. PoE++ enables higher power delivery through Ethernet cables, with a maximum of 90 watts per port. This is a significant increase from the previous limit of approximately 30 watts under IEEE 802.3at standards.

PoE++ standard uses all four wire pairs in a cable for power, boosting efficiency and supporting higher-powered devices like laptops and digital signs. This advancement allows for more PoE-powered technologies and is compatible with older PoE standards. It supports a variety of devices and applications while meeting the need for increased power delivery and efficiency in networked environments.

Comparison of IEEE 802.3bt PoE Mode A and Mode B

Two modes are available in the PoE++ standard: Mode A and Mode B.

  • Mode A: It employs pins 1-2 and 3-6 for both data and power transfer, leaving pins 4-5 and 7-8 unused. This mode is commonly associated with end-span equipment.

  • Mode B: This mode uses all pin pairs effectively. Data is transmitted through pins 1-2 and 3-6, while power flow is allocated to pins 4-5 and 7-8. These pins are often referred to as spare pairs or phantom pairs. Devices that utilize Mode B are recognized as Midspan devices.

Paying attention to pin configurations is crucial to avoid device incompatibility and inefficiency.

Key Features of IEEE 802.3bt PoE

  • Increased Power Delivery: 802.3bt, offering up to 90W per port, can power demanding devices like digital signage and high-performance wireless access points.

  • Efficient Power Management: It incorporates advanced power management capabilities, allowing for more efficient utilization of energy and reducing operational costs.

  • Backward Compatibility: Devices designed for earlier PoE standards can still be powered by 802.3bt sources, ensuring compatibility and ease of integration.

  • Improved Data Capabilities: While primarily focused on power, 802.3bt also supports 10GbE over Ethernet cables, enabling faster data transfer rates along with power.

When Do You Need IEEE 802.3bt?

PoE++ is necessary when devices need over 25W of power or when too many cables between devices reduce network efficiency. Certain devices such as security cameras, high-performance access points, and digital signage demand power levels exceeding 25W, making them compatible with 802.3bt PoE. If you possess such devices and require additional power outlets in proximity to them on your network switch or patch panel, 802.3bt PoE is essential.

Upgrade Your Network Infrastructure

As you work to enhance your network infrastructure and take full advantage of PoE++ technology, it's critical to assess power requirements and the devices that will be connected. While you can accomplish some of these tasks alone, working with an IT professional is critical to successfully upgrading your infrastructure.

FS PoE++ switches

The first step toward preparing for this changeover is upgrading your network devices, like switches, which support 802.3bt standards. In this setting, FS PoE switches show their significant benefits. These switches are not only fully compliant with the latest PoE++ standard but also offer a high-density PoE port configuration that can power more devices directly over the network cables, greatly simplifying network deployment and management. In addition, FS PoE switches are designed with future network expansion needs in mind, providing high performance, stability, and flexibility to ensure your network can easily expand as your business needs increase.

With FS's PoE switches, you can not only improve the efficiency and reliability of your network infrastructure but also ensure security and energy efficiency, as these switches also come with advanced network monitoring and security features. Whether it's for a complex network environment that needs to support a large number of high-powered PoE devices, or for a small business simply looking to modernize its network infrastructure to improve efficiency, FS PoE switches are ideal for upgrading your network.


To sum up, IEEE 802.3bt is the future of network infrastructure, offering the capacity to power higher-demand devices efficiently and introducing significant enhancements for data and power delivery. Ready to future-proof your network and elevate its capacity? Consider upgrading to 802.3bt-compatible devices now and witness a transformative leap in networking efficiency and capability.

You might be interested in

See profile for Migelle.
PoE vs PoE+ vs PoE++ Switch: How to Choose?
May 30, 2024
See profile for Charlene.
Understanding PoE Standards and Wattage
May 30, 2024
See profile for Sheldon.
Decoding OLT, ONU, ONT, and ODN in PON Network
Mar 14, 2023
See profile for Irving.
What's the Difference? Hub vs Switch vs Router
Dec 17, 2021
See profile for Sheldon.
What Is SFP Port of Gigabit Switch?
Jan 6, 2023