What Is The 802.3at PoE Standard?
The currently best performing PoE standard is IEEE 802.3at which allows for up to 30W of power to the PoE-device. That’s sufficient power for devices such as VoIP phones, wireless access points, and security cameras. But it’s not enough for
technology like flat screen displays, LED lighting, or retail POS terminals.
What is the 802.3bt PoE Standard And Its Voltage?
To meet the demand for higher power, the IEEE is set to release a new PoE standard to significantly increase capacity. IEEE 802.3bt will allow for up to 60W to 100W of power at the source by providing power over four pairs of wires (compared to the previous
technology’s ability to power over just two pairs). This increase in power allows you to use PoE for a greater range devices and applications. As an added benefit, the new standard will boost energy efficiency by minimizing power loss in the
cable—potentially cutting power loss in half.
Speeds Supported by Power over Ethernet 802.3bt
The new standard will include support for 2.5GBASE-T, 5GBASE-T and 10GBASE-T, while existing standards have a maximum speed of 1 gigabit. This new support will create intermediate data speeds between existing standards. Even though the new standard has
not yet been ratified by the IEEE802.3bt, Type 3- and Type 4-compatible products are already on the market.
PoE Types And Voltage
PoE Type 1 and PoE Type 2
Previous PoE technology included PoE Type 1 -also called IEEE 802.3af- and PoE Type 2, better known as 802.3at or PoE+. Both utilise 2-pair Power over Ethernet, Type 1 with a maximum of 15.4W per port and Type 2 with a maximum of 30W per port.
Type 3 and PoE Type 4
With the new 802.3bt standard come two new options: Type 3 and Type 4.
Type 3 is also called 4-pair PoE, 4P PoE, PoE++, or UPOE. It provides 60W of power per port and is ideal for video conferencing equipment and building management devices.
Note.In 2014, Cisco released a proprietary solution in advance of the new standard that could deliver up to 60W of power over all four pairs of wires after negotiation. This technology, called Universal Power over Ethernet (UPOE), will likely remain an
option even after 802.3bt is approved.
Type 4 (another designation is high power PoE) offers the highest power capabilities—potentially up to 100W of DC power (71W to each device)- and can support flat screens and laptops
PoE Applications And Benefits
- Use one set of twisted-pair wires for both data and low-wattage appliances.
- In addition to the applications noted above, PoE also works well for video surveillance, building management, retail video kiosks, smart signs, vending machines, and retail point-of-information systems.
- Save money by eliminating the need to run electrical wiring.
- Easily move an appliance with minimal disruption.
- If your LAN is protected from power failure by a UPS, the PoE devices connected to your LAN are also protected from power failure.