The terms PoE+ or PoE++ refer to the power budget available for the device.

See table below

Comparison of PoE parameters
Official name
in IEEE 802.3		 Type 1 Type 2 Type 3 Type 4
Common name(s) PoE PoE+ PoE++ / 4PPoE
Defining IEEE document 802.3af 802.3at 802.3bt
Power available at PD 12.95 W 25.50 W 51 W 71.3 W
Maximum power delivered by PSE 15.40 W 30.0 W 60 W 90 W
Voltage range (at PSE) 44.0–57.0 V 50.0–57.0 V 52.0–57.0 V
Voltage range (at PD) 37.0–57.0 V 42.5–57.0 V 41.1–57.0 V
Maximum current Imax 350 mA 600 mA per pair 960 mA per pair
Maximum cable resistance per pairset 20 Ω 12.5 Ω
Power management Three power classes (1–3)negotiated by signature Four power classes (1–4)negotiated by signature or 0.1 W steps negotiated by LLDP Six power classes (1–6)negotiated by signature or 0.1 W steps negotiated by LLD Eight power classes (1–8)negotiated by signature or 0.1 W steps negotiated by LLDP
Derating of cable maximum ambient operating temperature None 5 °C with only two pairs active, at Imax 10 °C with all of the bundled cables pairs active, at Imax 10 °C with temperature planning required
Supported cabling Category 3 and Category 5 Category 5
Supported modes Mode A (from Endpoint PSE), Mode B (from Midspan PSE) Mode A, Mode B Mode A, Mode B, 4-pair mode 4-pair mode mandatory