What is PoE?

Power over Ethernet (PoE) is an IEEE-standardized technique that delivers electrical power to networked devices – access points, IP cameras, VoIP phones – over the same twisted-pair cable that carries data, removing the need for a separate power outlet at every device. Versa CSG appliances supply PoE, PoE+, and PoE++ directly from built-in LAN ports or optional NIC modules.

Key takeaways

• PoE sends power and data over one Ethernet cable, no extra outlet needed.
• Three IEEE tiers exist: PoE (802.3af), PoE+ (802.3at), and PoE++ (802.3bt).
• Power sourcing equipment (PSE) supplies power; a powered device (PD) draws it.
• CSG1000 and CSG3000 appliances ship with built-in PoE LAN ports; the CSG700 adds PoE via an optional NIC module.
• Optional NIC modules add PoE/PoE+ ports beyond an appliance’s built-in supply.

On this page: Why it matters · How it works · Types · PoE & Versa · FAQ

Why is PoE important?

PoE matters because it decouples device placement from electrical wiring. A ceiling access point or an outdoor camera needs power and a network connection; running an electrician-installed outlet to each spot is slow and costly, while the Ethernet cable already has to reach the device for data anyway. Collapsing both into one cable run is why PoE became the default for access points, IP surveillance, VoIP handsets, and IoT endpoints.

It also simplifies operations. Because power flows from a switch or gateway port rather than a wall outlet, administrators can power-cycle a frozen access point remotely, monitor per-port draw, and budget power consumption centrally instead of tracking scattered adapters. For branch deployments, that mix of lower cabling cost, flexible placement, and centralized control is what makes PoE a standard LAN port spec, not a convenience.

What is PoE?

A PoE link has two roles. Power sourcing equipment (PSE) – typically a switch or gateway port – detects whether a connected device requests power, negotiates how much it needs, and supplies it. Powered devices (PD) draw that power: access points, cameras, and phones. Before power is applied, PSE and PD run a detection handshake so non-PoE devices, like a laptop, are never energized by mistake.

Power travels over the same CAT5e-or-better cabling used for data, either on the pairs already carrying the signal or on the pairs left spare in 10/100BASE-T links. The power budget depends on the standard and port: individual ports typically supply up to 30 W, while a device’s overall PoE budget is the sum of what all its powered ports can draw at once.

Types of PoE

Three IEEE generations define how much power a port can deliver, and each is backward compatible with the ones before it. PoE (IEEE 802.3af), the original 2003 standard, supplies up to roughly 15.4 W at the source – enough for basic access points and IP phones. PoE+ (IEEE 802.3at, Type 2), ratified in 2009, raises that to about 30 W per port, covering higher-power access points and pan-tilt-zoom cameras. PoE++ (IEEE 802.3bt), finalized in 2018, adds two further classes that push per-port power up to roughly 60 W or 90 W at the source, enough for PTZ cameras with heaters, thin clients, and multi-radio access points. Devices negotiate down to whichever tier both ends support, so a newer PoE++ port safely powers an older 802.3af device at its lower rating instead of over-driving it.

PoE & Versa

Versa CSG appliances build PoE support directly into their LAN ports. The CSG700 series adds PoE on four ports through an optional 60 W (NIC-4GP) or 120 W (NIC-4GP-120) NIC module, both supporting 802.3af and 802.3at at up to 30 W per port; total draw rises from 35 W with PoE disabled to 60 W enabled. The CSG1000 series ships with eight built-in PoE (30 W) LAN ports and a 240 W budget, extendable to twelve ports with an optional PoE+ NIC. The CSG3000 series goes further with eight built-in PoE++ (60 W) and sixteen built-in PoE (30 W) LAN ports, up to 800 W maximum consumption, and an optional NIC-4GP-120 module for added capacity. Across all three, PoE lets a CSG appliance power branch access points, cameras, and phones without separate injectors.

Frequently asked questions

What is the difference between PoE, PoE+, and PoE++?

They are successive IEEE power tiers on the same cabling: PoE (802.3af) delivers about 15.4 W per port, PoE+ (802.3at) about 30 W, and PoE++ (802.3bt) up to roughly 60–90 W. Each newer tier is backward compatible, so a PoE++ port can still safely power an older PoE-only device.

Which devices commonly use PoE?

Wireless access points, IP phones, and IP surveillance cameras were the original targets; PoE now also powers IoT sensors, badge readers, and building-automation endpoints. Higher-draw devices, such as PTZ cameras with heaters, typically need PoE+ or PoE++ rather than the original 802.3af tier.

Does PoE work over any Ethernet cable?

PoE requires at minimum CAT5e cabling; older CAT3 or damaged cable can’t reliably carry the currents involved. The PSE and PD also run a detection handshake before power is applied, so a cable run alone doesn’t guarantee delivery – both ends must support PoE.

How much power can a PoE port deliver?

It depends on the standard: roughly 15.4 W for 802.3af, 30 W for 802.3at, and up to 60–90 W for 802.3bt, measured at the source. A device’s total PoE budget is separate – it caps how much all powered ports can draw at once.

Do Versa CSG appliances support PoE?

Yes. CSG700, CSG1000, and CSG3000 appliances support PoE on LAN ports, either built in or via optional NIC modules, spanning PoE, PoE+, and PoE++ depending on the model – see the CSG hardware guides for exact port counts and budgets.

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