What Is PoE and PoE Switch?
What is PoE? PoE technology was defined by the IEEE 802.3af standard in 2003. Under this standard, the PoE allows a PD (powered device) like VoIP phone to receive up to 12.95W PoE wattage, utilizing just two of the available four twisted pairs in Ethernet cabling.
Then what is a PoE switch? PoE switch refers to an application of PoE technology. Functioning as a kind of PSE (power sourcing equipment), a PoE switch can supply power to PDs via Ethernet cables to realize network connectivity. Generally, an 802.3af switch supports max power consumption of up to 15.4W per PoE port with a voltage range between 44V and 57V. And the voltage range of PDs, connected with the PoE switch, is from 37V to 57V.
What Is PoE+ and PoE+ Switch?
PoE+ technology (IEEE 802.3at standard) is an upgrade of PoE technology, which was published in 2009. PDs in the market tend to require more wattage, like wireless access points that require PoE wattage of more than 12.95W to work normally. To solve that, here comes the PoE plus technology, which can support high power consumption.
Similar to a PoE network switch, the PoE plus switch also supplies power over two pairs, but it adds an additional power class that is able to deliver power up to 25.5W for a PD with a voltage range from 42.5V to 57V. The max power delivered by each port of a PoE+ switch is 30W, along with a voltage range from 50V to 57V.
What Is PoE++ and PoE++ Switch?
In the pursuit of adding more power to broader device applications, the IEEE 802.3 standard once again is required to upgrade its PoE+ technology to PoE++ (IEEE 802.3bt standard) in 2018. PoE++ can be classified into two types: Type 3 and Type 4. Type 3 enables two or all four twisted pairs in a copper cable to deliver power at a PD of up to 51W. Type 4 is up to 71W at a PD over four twisted pairs in an Ethernet cable.
PoE++ network switch is the next generation of PoE+ technology. PoE++ switch supports up to 60 watts of power to each port under Type 3 and offers the highest level of power for Power over Ethernet switches -- up to 100W on each PoE port under Type 4.
PoE vs. PoE+ vs. PoE++ Switch: Which to Choose?
As choosing a PoE switch should depend on different requirements, this part offers the information for making the optimal choice of four types of Power over Ethernet switches from two aspects: specifications and applications.
Specifications of PoE vs. PoE+ vs. PoE++ Switch
Based on the above-mentioned introduction, a reference chart that summarizes detailed specifications among PoE vs PoE+ vs PoE++ switches is presented below.
Note: the presented figures are just valuable in theory, while the total power capacity of PoE series switches in the application will be oversubscribed with more ports for many devices using less than maximum power. For instance, if you have a switch with all PoE++ Type 4 ports, it does not mean you will use all of them at maximum load 24×7. Consequently, you need to calculate the power requirements for all the powered devices that you plan to connect to the switch and select corresponding patch cables for your PoE design.
Applications of PoE vs. PoE+ vs. PoE++ Switch
Evidently, the major differences among PoE vs. PoE+ vs. PoE++ switches lie in their working mode and power supply, which reflect in their applications.
PoE switch
Basic VoIP phones operating across the public internet
Two-antenna wireless access points for small networks
Stationary security cameras without pan, tilt, and zoom
Sensors, meters, etc.
PoE+ switch
IP telephones that offer fax, text messaging, and voice calls
Wireless access points with six antennas
Remote-controlled pan, tilt, and zoom (PTZ) surveillance cameras
Biometric sensors that collect biological characteristics
PoE++ switch
Two-way video phone calls in a conferencing system
Building management devices such as gate or door controllers
Thin clients connected remotely to a server-based computing environment
Remote patient monitoring devices
