A friend asked whether you can use the telephone line to connect the POE or use the four cores of the network wire to do the crystal head, many friends are confused is the network cable 1236 and 4578 which power supply? We have also sent a similar article on this question, today we come again to have a comprehensive understanding.
1. Which exactly transmits data and which supplies power
Standard poe switches have two standards, 802.11af and 802.11at, and both standard poe switches support two modes:
① 1236 takes both data and power supply;
② 1236 go data, 4578 power supply;
2. Which kind of power supply method is actually used
Which power supply mode is actually used depends on the POE switch, which are both compatible with our POE-enabled cameras. The poe will judge it by the situation.
Due to the 1,2,3, and 6 four cores used by 100 megabytes of communication, the gigabit megabytes of communication uses all 8 cores.therefore:
1. For 100 trillion PoE switch: only 1,2,3,6 wire core connected, both data and power supply; of course, if you want 1236 data, 4578 power supply, then 8 cores wire, and ensure 8 cores all connected.
2. For Gigabit PoE switch: limited by the need of data transmission, no matter in that way, all the 8-core network wires need to be fully connected.
3. What are the two criteria for a POE switch
The IEEE802.3af power supply power is 15.4W, if the camera power is 10W, the 802.af power supply switch can be used;
IEEE802.3at power supply power is 30W, if the camera power is 20W, 802.3at POE switch should be used;
802.3at is downwards compatible, so 802.3af-enabled cameras can be powered by 802.3af or at switches;
802.3at-enabled cameras are only powered by 802.3at switches;
For some high-power front-end equipment, such as the ball machine, the output power can not meet the requirements, can not be P the POE switch.
For example, the power of some ball machines is 40W, and the maximum power of single port PoE is not more than 30W, so the power of single port of the switch cannot be met, so the POE module of the ball machine is needed. I saw it right when I bought it.
4. How far is the POE supply?
For the poe power supply distance, there have been many weak current VIP technology group friends discussing whether can the poe power supply exceed 100 meters? This problem is indeed affected by many factors, some friends more than 100 meters of power supply has no impact, but some in the 90 meters of power supply has also been unstable, which we will discuss together.
You must see the 200 m, 250 m, 300 m PoE power supply switch products advertised on Moments or online. There will be a doubt: the network cable transmission distance is not 100 meters? What line can be used to achieve the distance of propaganda?
More than 100 meters of long-distance transmission must be more than 5 categories, and is 8 core network wire. At the same time, the poe switch is powered by 8 cells, and the camera must also be powered by 8 cells. The key point is that the PoE switch equipment supports the network extension mode. After turning on, when using the data transmission and above network cable, the power supply distance of the corresponding port can reach more than 100 meters. For the ordinary poe switch, we suggest that it is more appropriate within 100 meters.
Why is it recommended to use it within 100 meters?
Let’s look at the resiresistance of various network wires.
Resistance of 100 meters of various material types of twisted pair wire:
1. Copper-clad steel network wire: 75-100 Ω
2. Copper-clad aluminum mesh wire: 24-28 Ω
3. Copper package silver network cable: 15 Ω
4. Copper-coated copper network cable: 42 Ω
5. Anaerobic copper mesh wire: 9.5 Ω
The shorter the distance, the smaller the resistance, where the anaerobic copper network wire resistance is the smallest, so use it to supply the most stable, 100 meters distance resistance is only 9.5 Ω, what if the use is 50 meters? Then its resistance is 9.5 Ω half, the smaller the poe power supply loss (loss of power formula, Q=I²Rt, the loss of power is proportional to the resistance), then the more stable the power supply. So more than 100 meters of distance transmission, be sure to use a good network cable.
Post time: Nov-02-2022