Q&A about PoE Switches

Dec 20 , 2022 1469

The development of PoE power supply technology is gaining momentum. With its advantages of simplified installation of electrical equipment, deployment, energy saving and safety, PoE technology has been widely used. Today we will sort out the frequently asked questions and answers about PoE switches.

Q1: PoE is so convenient and has been applied widely, but is it stable?

A: From a technical point of view, PoE technology has been developed for many years, so it is now in a relatively stable stage, and standard PoE power supply is sufficient and stable. However, due to the low cost pressure in the current market, the selection of PoE switches is relatively poor, or due to the constraints of the solution, excessive loading, etc., it is easy to cause unstable power supply. Remember, this is not the reason for PoE power supply, but reason of human factors.

In security projects, the amount of data transmission is quite large, and the requirements for power are very high, and equipment is required to work uninterruptedly all day long, so the usage of guaranteed PoE equipment and wires are the reassurance for the stability of the entire system.

Q2: Can PoE function really save power?

A：We often say that one of the great advantages of PoE function is energy saving, so what aspects of PoE power supply can save power? Let's take the GN series switches as an example to illustrate. The PoE switch will automatically adjust the power supply according to the power supply equipment. For example, when the loaded camera automatically turns on the heating function at low temperature, the power consumption will increase, then the switch will automatically adjust the power supply according to the status of the camera at this time. We have said that when the switch supplies power, it needs to go through several stages, from providing a small voltage for testing at the very beginning, to finally supplying the power steadily, and it will automatically cut off the power in case of failure to maintain the safety of the equipment.

Q3: The higher the power of the PoE switch, the better?

Since most of current surveillance equipment is high-power equipment, switch manufacturers tend to develop PoE switches with higher power. However, many products on the market only pursue the provision of total power, and do not consider about the number of ports. When the power is increased, it will also increase the overall cost of the equipment, as well as purchase cost. Therefore, when purchasing, the users must select the appropriate switch according to the actual situation, not the higher the power, the better.

Q4: What are the risks of PoE in the power supply process?

A: First, insufficient power. The 820.af standard PoE output power is less than 15.4w, which is enough for general IPCs, but for high-power PDs, the output power cannot meet the requirements;

Second, too concentrated risks. The switch has multiple ports, and each port has a bridging function, which can be connected to a local area network or a high-performance server or workstation. In fact, switches sometimes are called multiport bridges. Generally, a PoE switch will supply power to a variety of front-end IPCs at the same time. If the power supply module of the switch fails to work, it will affect all equipment linking to it, and the risk is quite concentrated;

Third, high equipment and maintenance costs. Compared with other power supply ways, PoE power supply technology will increase the workload of after-sales maintenance. From the perspective of safety, the stability of independent power supply is the best. 

Q5: Is it necessary to buy a standard PoE switch? Can non-standard PoE switches be used?

A: Choose standard or non-standard, this mainly depends on how much voltage the AP and IP Camera support? Does it support 48, 24, or 12v? If it supports 48v, you need to choose a standard PoE switch; if it supports 24v or 12v, you need to find a corresponding non-standard switch, of course standard ones are also available, but if you buy a standard one, you need to be equipped with a PD splitter.

From the description, we can see that sometimes non-standard switches are also available, and the price will be relatively lower. However, everyone is still suggested to buy standard switches. Considering the fact that the non-standard switch does not have a PoE chip. Without detecting the device, it is easy to cause a short circuit to burn out the ports, the or even cause a fire, while the standard switch will detect when it is powered on to avoid burning out the device.

Q6: Does the standard PoE switch have high reliability?

A: The reliability of equipment is closely related to the operating environment. Commercial switches are generally used indoors, while industrial switches are used outdoors in harsher environments. The PoE power supply line generally consists of two parts, namely a switching part and an external power supply unit for PoE power supply. Therefore, the power supply unit is responsible for the entire power supply, so reliability is of the utmost importance. Consequently, if the standard PoE switch supplies power, the line is relatively stable.