PoE switches are used in various fields such as video surveillance, wireless coverage, IP telephony, access control, alarm, etc. PoE switches are also involved in a wide range of networking applications. PoE switches are used in more complex transmission systems such as weak power communication, industrial Internet of Things, security transmission networks, etc. The scale of networking is getting larger and larger, and the area covered by the network is also getting wider. The web is getting bigger and bigger. And the area covered by the network is getting broader and broader. Users are more concerned about PoE switches‘ network communication transmission distance and the distance of stable power supply over Ethernet when they choose PoE switches. PoE switches of various transmission distances have emerged, 100 meters, 150 meters, 250 meters, and even 800-meter transmission distance PoE switches flooded in the PoE market to let users know more about PoE switches the application of transmission distance knowledge and considerations. Today Mr. Hua will tell you about the PoE switch transmission distance. Today, Mr. Hua will say to you about the PoE switch transmission distance.
Why the international standard network transmission distance is 100 meters?
Weakness engineers know that the optimal transmission distance of network transmission is 100 meters. What caused the upper limit of 100 meters transmission distance of twisted-pair cable? It is to look deeper into the profound physical principles of a twisted-pair line. Network transmission is the network signal transmission on the twisted-pair cable. As an electronic signal, it must be affected by the resistance and capacitance when it is transmitted in the twisted pair, leading to the network signal’s attenuation and distortion. The signal attenuation or distortion reaches a certain level. It will affect effective and stable signal transmission. So, twisted-pair cables have a transmission distance limit.
So how exactly is the 100-meter limit calculated?
Category 5 UTP, Super Category 5 UTP is for computer networks; according to the Fast Ethernet 100Base-TX regulations, the communication rate of 100mbps, 100mbps Ethernet transmission of 1 bit of data spent time (aka “bit time”) can be calculated as follows.
1 bit time = 1/100mbps = 10ns
Ethernet is a shared communication channel using CSMA/CD (Carrier Sense Many Access with Collision Detection), Carrier Sense Many Access with Collision Detection (Carrier Sense Multipoint Access/Collision Detection). When introduced switching, it was still inseparable from this technology. Beyond 100 meters, the packet damaged by the collision is transmitted and is not received by the receiving party because it cannot detect the crash in time. This packet of information is forced to discard because it can not pass the authentication. Now, the mechanism of backward retransmission is not activated to cause the loss of packets. When the transmission rate is lower than 100 Mbps, 100 meters can be relaxed in practical applications. It must declare that this, although applicable, does not follow the standard. It must be stated during the certification test. Otherwise, it will create some problems, such as product warranties.
Whether you are 100 megabit network or gigabit network transmission distance on a theoretical basis, the choice of a transmission distance of one hundred meters or less is with the best transmission results.
Communication cable on PoE switch transmission distance and what is worth noting
In the international standard, the effective transmission distance of network cable is 100 meters. Yet, in practice, the transmission distance of different materials of network cable varies. Copper-clad steel network cable, or what we usually call a four-iron, four-aluminum line, usually has two copper-clad aluminum cores and two copper-clad iron cores. Generally, it can only use this type of cable in ordinary network situations and the best wiring in 80 meters. Copper-clad aluminum cable, with standard aluminum as the material, the outer layer of oxygen-free copper, is not complete, with a transmission distance of about 100 meters. The copper-clad silver wire is imported aluminum as the primary material. The outer layer is a whole layer of the oxygen-free copper layer.
Generally used in ordinary networks, it can send 160-180 meters in a single network environment. But it is not durable. Copper-clad aluminum network cable and copper-clad silver network cable are easy to oxidation. The public life is not very long, about 3-5 years—All-copper network cable, also known as bronze network cable, copper-clad copper network cable. The primary material is back to the copper, the outer layer of oxygen-free copper plating. Due to the copper purity is not high, the general transmission distance is about 80-100 meters. Oxygen-free copper network cable, the primary material is very high pure copper, can do high-quality network cable, and can generally be transmitted to 100 meters – 120 meters. That is, the transmission distance of the network cable material has a significant relationship. The network cable transmission distance and the size of the conductor also have a lot to do—the thicker the conductor, the greater the effective length of transmission. The conductor sizes of Category 5 and Super Category 5, and Category 6 cables are different. Category 5 cable is below 0.45, Super Category 5 is around 0.45-0.51, and Category 6 cable is about 0.52-0.58. The conductor material and conductor size also affect the resistance of the network cable. The worse the conductor material, the higher the resistance. The thicker the conductor, the lower the resistance. Networks with low resistance can send over long distances.
Is a PoE switch with a 150-meter transmission distance reliable?
The data signal transmission distance determines the PoE power supply distance. It can send pure electricity far, but the network cable determines the data signal transmission distance. Ordinary Category 5 wire data signal transmission distance is about 100 meters. Engineering to ensure the quality of construction takes 80-90 meters. Please note that the transmission distance here refers to the most significant rate, such as 100M. Many PoE manufacturers have labeled their PoE switch transmission distance can being 150 meters. Still, in practice, the ordinary PoE switch to achieve 150 meters transmission distance, the quality of network cable has strict requirements, you must use more than six types of wire, which also increases the cost of use. If the PoE switches internal circuitry using a widespread network switching chip and PoE power supply management chip, reach the network 100M and 150 meters transmission distance. Even with a high-quality network cable, it is unlikely to increase power consumption beyond that of a PoE power supply and is unstable with severe packet loss. Transmission bandwidth and signal attenuation, resulting in unbalanced signals. POE transmission distance of 150 meters PoE switch itself is garbage. It is unreliable.
250 meters of transmission distance PoE switch and what is the matter?
Mr. Hua has analyzed the technical situation of 150 meters transmission distance. The high-performance PoE switch using the best quality network cable 100M full load stable transmission can only reach 150 meters. Two hundred fifty meters transmission distance and what is going on there are pits, the primary use of the rate down to 10M. The transmission bandwidth of 10M can extend the transmission distance. To 250 meters (the same need to consider the quality of the network cable depends). This technology does not provide high bandwidth; bandwidth from 100M into a compressed 10M does not help the smooth transmission of high-definition monitoring images. Many manufacturers promote their products to support 250 meters of communication while the transmission bandwidth down to 10M is not mentioned. There is a suspicion of deliberate concealment of customers. HoweVision, in the design of PoE switch transmission 250 meters, will generally design a changeover switch for users to choose whether to use. In the non-essential use of long-distance PoE, let the product work on a high-performance transmission effect rather than the long-distance mode. Of course, Mr. Hua needs to remind user friends that not all PoE switches can send 250 meters as long as they are reduced to 10M bandwidth, which also depends on the quality of the switch. Suppose the switch’s internal switching chip adaptive capability is too poor, and the power chip management capability is weak. Even if it is forced to 10M transmission, it cannot achieve 250 meters stable transmission or reach 150 meters. HoweVision has tested many PoE switches claiming 250 meters transmission, using super-category five strict standard network cable. The most non-professional manufacturers brand in the information of more than 130 meters even the network signal is gone, not to mention 250 meters.
HoweVision company is how to ensure and realize the PoE switch 250 meters stable transmission function?
First of all, we should do PoE management upgrade function well. The transmission distance of 250 requirements, PoE using high-power design, and a PoE power chip using imported high-quality industrial-grade chips. The power management module can identify the IEEE802.3af/at standard dual-mode innovation, automatic power change, the use of full-load high-performance communication switching power supply, automatic measurement of the power demand of the receiving end, and cable transmission impedance, and other parameters. The intelligent power management module analysis and calculation issued instructions to the internal power circuit to adjust the linear voltage input to match the automatic power output to the end of the powered equipment. Due to the extension of the cable distance, the probability of the cable being damaged increases. But it also needs to design an overcurrent/ overvoltage protection circuit. While PoE standard design, automatic long-distance identification of PD devices, intelligent power supply, stable and reliable, eliminates the burner. , do an excellent job of upgrading the network transmission capability function; choose the strong data capability of the communication chip and increase the choice of backplane bandwidth. Enough data processing margin must use the store-and-forward mode, improve the data error correction capability of data transmission over long distances, must support the line speed forwarding function. Support long frame transmission capability, offsetting the transmission efficiency slowed by the long-distance error correction by improving forwarding speed if The use of ordinary switch chips and design to achieve 250 meters transmission distance is impossible. Finally, selecting high-quality network cable up to standard network cable networking, long-distance transmission requirements must have strict requirements for the network cable. If the network cable quality is imperfect, it will reduce the transmission distance.
Long-distance PoE other types of features and product models summarized and analyzed.
The most critical issue to achieve a long-distance 800 meters transmission distance is the signal change. An external signal modulation chip is currently on the market to target the secondary processing of IP/TCP signals and increase the port power supply under the dual model to achieve the long-distance transmission 800 meters. At present, the industry has not been recognized for this type of processing. First of all, the authorities may not recognize the secondary processing to adapt to the long-distance transmission of digital and network signals in the application of docking with other equipment signal reliability and stability. , the distance is too long. Line loss is too significant. The port power load brings more pressure. Long-distance power supply generally uses high-voltage AC power supply is more energy-efficient. PoE belongs to low-voltage DC, more in line with the power supply value for near-term terminal equipment. It is recommended that the long-distance PoE power supply does not exceed 300 meters is better. More than 300 PoE networks should be considered in the network design to increase the PoE application deployment points.
PoE repeater / PoE extender to achieve increased transmission distance does not reduce the quality of transmission applications. In domestic and international engineering applications, the first to solve short local PoE transmission distance is PoE repeater / PoE extender choice. The product is easy to apply, fast and flexible, more in line with the project application’s actual needs than the long-distance PoE switch. The disadvantage is that the PoE repeater/PoE extender costs more. Also, the PoE repeater/PoE extender product itself requires power consumption, increasing the burden of power supply to the PoE port. The fact that node laws limit them during transmission (HoweVision experiences no more than 3 PoE repeaters/PoE extenders on a line).
HoweVision says communication. I am Mr. Hua, technology 100%, original 100%, talk about PoE technology and stories, and promote communication technology to a broader future! Today’s “How to choose a long-distance POE switch and attention to the problem” is shared here. What kind of views do you have on PoE switch transmission distance issues? You are welcome to leave a message for Mr. Hua. Thank you for checking out more PoE stories and more. See you next time!
