Introduction to PoE Power Line Connection

- Sep 05, 2017-

PoE power through the network cable, there are four pairs of line order, and now directly buy our PoE switch or other PoE devices can be plugged in power supply, regardless of line order problem. Although basically do not have to consider PoE power supply line order, but let me introduce it to you.

PoE power supply line sequence method:

The IEEE802.3af / at standard allows PoE to have three types of power supply lines:

1, the line 4,5 line is positive, 7,8 line is negative;

2, the cable in the 1,2 line is negative, 3,6 line is positive;

3, the line in the 1,2 line is positive, 3,6 line negative;


10M and 100M data network, the data signal transmission only used 1 2 3 6 pairs of lines, Gigabit network 4 pairs of lines are used.

10/100 DC on Spares (mode B): 10M / 100M network idle to power supply

10/100 Mixed DC & Data (mode A): 10M / 100M network data on power supply

1000 (1 Gigabit) DC & Bi-Data (mode B): Gigabit Network Mode B 4 5 7 8 Power supply

1000 (1 Gigabit) DC & Bi-Data (mode A): Gigabit Network Mode A 1 2 3 6 Power supply

Tx on behalf of the data sent, Rx on behalf of the data received, TxRx that is sent and received.

Above for the IEEE 802.3af and IEEE 802.3at cable line order, please note that the pair of lines, whether it is af or at, are positive, if the product 4 5 for the negative line, then non-standard PoE products. 802.3at 4 pairs are 4 pairs of lines are powered, PSE output power up to 60W or more, PD received power 51W or more.

poe power supply connection.jpg

poe power supply.png

T568A Color, T568B Color is a little different. The international standard stipulates that there are two kinds of network cable order: 568A and 568B, under normal circumstances in accordance with the 568B standard majority, both rows of order: 1 white orange, 2 orange, 3 white green, 4 blue, 5 white blue, 6 Green, 7 white brown, 8 brown (which will be one of the 1 and 3,2 and 6, respectively, for the 568A standard). 568A and 568B, there is no essential difference between the two, but the difference between the color, the essence of the problem is to ensure that:

(1) 1,2 pairs of pairs is a pair

(2) 3, 6 pairs is a pair of around

(3) 4,5 line pair is a pair of around

(4) 7, 8 pairs of pairs is a pair

In order to avoid construction errors, it is recommended to use T568B class connection.

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