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Six Questions About The Usage Of PoE (Part 2)

Time：2021-04-27 Source：UTEPO

1. IS POE STABLE?

PoE technology has been developed for many years and is now at a very mature stage, and the standard PoE power supply is stable and safe enough. Most of the unstable situation would be due to the followings:

l The choice of passive PoE switches.

l The quality of cables is too poor.

l The program design itself is not reasonable.

l The power supply distance is not proper.

l Too many high-power devices connected, and it causes the shortage of power supply (especially the monitoring equipment enable heating mode at night).

So you'd better investigate the external causes first when found the issue of an unstable power supply.

2. IS THE POWER OF THE POE SWITCH HIGHER THE BETTER?

Due to the emergence of high-powered devices such as HD dome cameras and real-time video phones, network equipment manufacturers are scrambling to develop PoE switches with a higher power. However, many manufacturers only pursue the increase in the power budget while ignoring the relationship between power and the number of ports. It would inevitably increase the overall cost of the equipment when the power is high. And the result is that the user chooses a PoE switch with low practicality and low-cost performance. Therefore, you should choose the most suitable PoE switch based on the determined power and number of PD devices according to the steps in Question 1.

3. WHY IS THE TRANSMISSION DISTANCE OF POE LIMITED TO 100 METERS?

The maximum transmission distance of the PoE switch mainly depends on the data transmission distance. When the transmission distance exceeds 100 meters, data delay and packet loss may occur. Therefore, in the actual construction process, the transmission distance is best not to exceed 100 meters.

On the other hand, in addition to the PoE quality, the distance also depends on the network cables. Poor quality of network cable would limit the transmission distance. Besides, the farther the transmission distance is, the greater the resistance would be. It would have higher requirements on the network cable. To reduce the occurrence of failures, the transmission distance is recommended within 100 meters.

For some specific demands, UTEPO provides PoE switches with 250-meter transmission distance. But try to ensure quality of data and PoE, the rate would be limited to 10M.