PoE+ (802.3at)
Power over Ethernet · 9 specs
Direct Answer
Power over Ethernet Plus (PoE+, IEEE 802.3at Type 2) is a 2009 standard delivering up to 30.0 W of DC power per PSE port and guaranteeing 25.50 W of continuous power at the connected Powered Device (PD) across two twisted pairs of Category 5e or better cable.
Source: IEEE 802.3at-2009 (incorporated in IEEE 802.3 Clause 33) · Last reviewed Aug 28, 2026
Specs
| IEEE Standard | IEEE 802.3at-2009 |
| PoE Type | Type 2 (PoE+) |
| PSE Output Power (Max) | 30.0 W |
| PD Input Power (Guaranteed) | 25.50 W |
| PSE Output Voltage Range | 50.0–57.0 V DC |
| PD Input Voltage Range | 42.5–57.0 V DC |
| Max Current | 600 mA |
| Twisted Pairs Energized | 2 pairs (Alternative A or B) |
| Minimum Cable Category | Category 5e |
Power Increase and Classification Negotiation
PoE+ was ratified in 2009 to power higher-draw devices such as motorized Pan-Tilt-Zoom (PTZ) cameras and dual-radio Wi-Fi access points. It introduced 2-Event Physical Layer Classification (where the switch pulses voltage twice to identify a Type 2 PD) and LLDP (Link Layer Discovery Protocol) Data Link Layer classification.
LLDP negotiation allows devices to dynamically request fractional wattage adjustments in 0.1W increments, enabling switches to optimize overall PoE power allocation.
Backward Compatibility
IEEE 802.3at is fully backward compatible with legacy 802.3af. A PoE+ switch port will safely provide standard 15.4W to a legacy Type 1 device, and a PoE+ device plugged into an older 802.3af switch will either operate in a reduced-power fallback mode or alert the user of insufficient power.