With the application of POE switches becoming more and more popular, more and more friends began to have such doubts.

So today, let's have a comprehensive understanding.

Data transmission and Power Supply

Take 802.11af and 802.11at standard poe switches for example. They both support the following two power supply modes:

(1) 1236 Both power supply and data;

(2) 1236 runs data and 4578 runs power.

How is the power actually supplied?

The actual power supply mode depends on the POE switch.

Since the two power supply modes are compatible with cameras supporting POE, POE will determine which power supply mode to use according to the situation.

Since 100M communication uses 1236 four cores, and gigabit communication uses all eight cores, therefore:

Under the power supply standard of 100M POE switch, as long as the 1236 four core network cable is connected, data and power can be supplied. However, if you want to choose the second power supply method, you must use the eight core network cable and ensure all connectivity.

For gigabit POE switches, no matter which power supply mode is selected, due to the needs of data transmission, all 8-core connections must be guaranteed.

Power supply distance of POE switch

1. How far is the power supply distance?

I believe that many friends will often see various POE switch products on the network that promote power supply distances of 200m, 250m or even 300m. Therefore, it is inevitable that there will be a question: "Is the transmission distance of the network cable not 100m? What kind of cable can be used to achieve this distance?"

In fact, a transmission distance of more than 100m can be achieved, but it must be an 8-core network cable of more than Category 5.

The POE switch must be powered by eight cores, and the camera must also be powered by eight cores.

Another key point: POE switch equipment supports the network extension mode, so when this mode is enabled and more than five types of eight core network cables are used, the data transmission and power supply distance of its corresponding port can reach more than 100m.

However, we always suggest that it is more appropriate to be within 100m.

2. Why is this suggestion?

First of all, the resistance of network cable varies with its material.

Take the 100m length of super five twisted pair network wires made of copper clad steel, copper clad aluminum, copper clad silver, copper clad copper and oxygen free copper as an example. Among them, the oxygen free copper network wire has the lowest resistance, only 9.5 Ω, while the copper clad copper network wire has the highest resistance, 75-100 Ω.

Moreover, the shorter the distance is, the smaller the resistance will be. If it is a 50m oxygen free copper network cable, the resistance will be less than 5 Ω.

Therefore, the recommended distance of 100m can better reduce the power loss of POE and ensure the stability of power supply.

If the distance exceeds 100m, it will not only face greater power loss, but also must choose higher cost network cable.