Line order problem of power supply for PoE switches

Line order problem of power supply for PoE switches

PoE switches, cost-effective and easy to use, and plug and play, very convenient, but many people do not know the PoE switch power supply line order problem, 10 years focus on PoE research and development of small books, brief introduction to everyone

The IEEE802.3af/at standard allows the PSE to have three forms of power supply line order:

1, the network of 4, 5 line is positive, 7 and 8 line is negative.

2, the network of 1, 2 lines for the negative, 3 and 6 line is positive.

3, the network of 1, 2 line is positive, 3 and 6 line is negative.

Explanation: in 10M and 100M data networks, data signals are transmitted only to 1236, two pairs of wires, and Gigabit networks, 4 pairs of wires are used. In the corresponding PoE switches, 10/100M switches use 2 pairs of wire pairs, and Gigabit switches are all used.

International standards specify: there are two lines of network arrangement, namely 568A and 568B. Under normal circumstances, in accordance with the 568B standard in most, that is, row order: 1, white orange, 2 orange, 3 white, green, 4 blue, 5 white, blue, 6 green, 7 white brown, 8 Brown (1 and 3, 2 and 6, respectively, reversed for the 568A standard). 568A and 568B, there is no essential difference between the two, but the difference in color (in order to avoid engineering errors, it is recommended to use T568B), the essential problem is to guarantee:

(1) the pair of 1 and 2 lines is a round pair

(2) the pair of 3 and 6 lines is a round pair

(3) the pair of 4 and 5 lines is a round pair

(4) the pair of 7 and 8 lines is a round pair