How to Ensure Long-distance Transmission of Industrial POE Switch

PoE Industrial Switch supports output power up to 15.4W and 30W, and conforms to the IEEE802.3af standard. It supplies power to standard PoE terminal equipment by means of network cable power supply, eliminating the need for additional power wiring.After investigation, the poe switch developed and launched in line with IEEE802.3aT and IEEE802.3af standards, the port output power can reach 25-30W. In layman's terms, a PoE switch is a switch that supports network cable power supply, which can not only realize the data transmission of ordinary ethernet switches but also can supply power to the network terminal at the same time.

As we all know, the Ethernet standard stipulates that the maximum transmission distance is 100 meters. If the transmission distance exceeds 100 meters, data delay and packet loss may occur, because when the signals are transmitted in the twisted pair, they interfere with each other and are also affected by external electromagnetic waves. At the same time, due to the parasitic capacitance and parasitic inductance between the wires, the signal attenuation and distortion are caused. The accumulated signal attenuation after the distance is too long will not ensure the stable transmission of the signal.

But not all network cables are limited within 100 meters. In actual operation, network cables can also effectively transmit more than 100 meters, and good quality can reach about 120 meters, that is, oxygen-free copper Cat.5 network cables, or Category 6 network cables. This kind of line can effectively reduce its own interference, and also avoid the interference caused by the series connection and the outside world, so the transmission is farther. To put it bluntly, the distance of the power supply transmission distance depends on the quality of the network cable. It is possible to transmit power signals alone. More than 100 meters, it can even reach 200 meters.

Category 5 cable is the most common type of network cable on the market today, but the quality varies greatly. In order to reduce costs, many manufacturers replace copper wires with impurity copper, copper-clad iron, and copper-clad steel, which reduces the transmission distance of network cables. If you want to maximize the effect of industrial PoE switch, be sure to use a good quality network cable. Now many PoE switch manufacturers have launched 150 meters, long-distance 250-meter power supply, and even 500-meter transmission distance industrial POE switches. Doesn't it mean that the transmission distance of standard POE switches is 100 meters, and it is best to control the distance within 80 meters in actual use. What is going on? Let's find out.

Although many manufacturers have stated that the transmission distance of their industrial POE switches can reach 150 meters, in practical applications, in order to achieve a transmission distance of 150 meters for ordinary POE switches, there are strict requirements on the quality of network cables, and more than 6 types of cables must be used. It increases the cost of use. Even so, if the internal circuit of the industrial POE switch adopts a very common network switching chip and POE power supply management chip, it is impossible to achieve a network of 100M and a transmission distance of 150 meters, even if high-quality network cables are used. Reluctant use will lead to an increase in power consumption, exceeding the power consumption of PoE power supply, and it is very unstable, with serious packet loss, serious attenuation of transmission bandwidth and signal, resulting in unstable signal, aging of PoE switch equipment, and difficulty in later maintenance.

The high-performance POE switch can only reach 150 meters with full load and stable transmission. What is the transmission distance of 250 meters? In fact, there are ways. If the speed is reduced to 10M, that is, the transmission bandwidth is 10M, the transmission distance can be extended to 250 meters (depending on the quality of the network cable), this technology cannot provide high bandwidth, and the bandwidth is compressed from 100M to 10M, which is not convenient for high-definition and smooth transmission of monitoring images. While many industrial switch manufacturers advertise that their products support 250-meter transmission, they do not mention the bandwidth down to 10M, and they have the suspicion of deliberately concealing it from customers.

POE switches that transmit 250 meters generally design a transfer switch for users to choose whether to use them. But not all POE switches can easily transmit 250 meters as long as the bandwidth is reduced to 10M, which depends on the quality of the industrial switch. 10M transmission, can not guarantee the stable transmission of 250 meters, even 150 meters can not reach.

Therefore, to ensure the stable transmission of 250m, the industrial POE switch needs to adopt a high-power design, the POE power chip adopts imported high-quality industrial-grade chips, and the power management module can intelligently and automatically recognize the IEEE802.3af/at standard and automatically adjust the power. Intelligent power supply technology, to achieve such a function, use a built-in power supply. The advantage of using a built-in power supply is that the specific design can be optimized, and parameters such as the power demand of the receiving end and the transmission impedance of the cable can be automatically measured. The intelligent power management module analyzes and calculates, and issues The command to the internal power circuit regulates the linear voltage input to match the automatic power output to the end powered device. Due to the extension of the cable distance, the probability of the cable being damaged increases, and an overcurrent/overvoltage protection circuit is also designed. At the same time, the POE standard design also ensures that the non-POE equipment only transmits data, not power supply, stable and reliable, and eliminates the need for burn machine.

In a word, it is very difficult for poe industrial switches to reach 250 meters of transmission. There must be strict requirements for network cables, network switching chips and POE power supply management chips, otherwise the transmission distance will be greatly reduced.