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Which methods of power supply that PoE uses?

Time：2021-03-31 Source：UTEPO

There are two common standards for standard PoE switches, IEEE 802.3af and IEEE 802.3at, both of which support two power supply methods.

A. Data and power supply run over 1236

B. Data runs over 1236 and power supply runs over 4578

In current market, the PoE cameras support both of these two methods, so the actual use of which power supply depends on the POE switch.

Generally, the 100 megabit communication uses the 4 cores(1, 2, 3, 6), while gigabit communication uses all 8 cores.

For 100 megabit PoE switches, it could use a 4-core cable (1,2,3,6) to transmit both data and power supply. If you want the cable to transmit data over 1236 and the power supply over 4578, an 8-core cable would be needed. Also, you must ensure that all eight cores are connected.

Limited by data transmission requirement, no matter what kind of power supply methods, it needs to use the 8-core cable for the gigabit PoE switch, and all eight cores should be connected.

THREE POE STANDARDS

Standard	IEEE 802.3af	IEEE 802.3at	IEEE 802.3bt
Power (PD)	12.95W	25.50W	71.30W
Power (PSE)	15.40W	30.00W	90.00W
Voltage Range(PSE)	44.0-57.0V	50.0-57.0V	52.0-57.0V
Voltage Range(PD)	37.0-57.0V	42.5-57.0V	41.1-57.0V

IEEE 802.3AF

The PoE power of IEEE 802.3af is 15.4W, which is suitable for supplying power to 10W IP cameras

IEEE 802.3AT

The PoE power of IEEE 802.3at is 30W, which is suitable for supplying power to 20W IP cameras

IEEE 802.3at is backward compatible with IEEE 802.3af, so an IEEE 802.3af IP camera could be powered by the IEEE 802.3af or IEEE 802.3at PoE switch, an IEEE 802.3at IP camera could only be powered by the IEEE 802.3at PoE switch.

With PoE technology development, most PoE switches in the market could support both IEEE 802.3af and IEEE 802.3at now.

IEEE 802.3BT

The PoE power of IEEE 802.3bt is 90W. As PoE-powered IoT networks expand around the world, more and more power-consuming devices are born. Unfortunately, the PoE standard like IEEE 802.3at is only applicable to low-power devices with up to 30W of power through Ethernet, which limits the power available for smart networks and devices. This the reason the IEEE 802.3bt comes out and provides more power to more PDs like the LED light, cloud desktop, POS, etc.

UTEPO had launched bt PoE switches and repeaters last year, click below link to get more information.

>>> UTP7308GE-BTPOE90, UTEPO BT PoE Switch (90W*8)

>>> UTEPO Waterproof Industrial BT PoE Repeaters

Also, UTEPO provides the convenient tool for installers, which could test the standard of PD and PSE.

>>> UTEPO EPFast Tool

EPFast tool