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What is the maximum distance of data transmission of Ethernet Cable in meters?


What is the maximum distance of data transmission of Ethernet Cable in meters?


1. The maximum distance of Ethernet Cable data transmission

 Friends who know more about the network know that Ethernet Cable has an "insurmountable" transmission distance of "100 meters". Whether it is a Category 3 Ethernet Cable with 

a transmission rate of 10M, a Category 5 Ethernet Cable with a transmission rate of 100M, or even a Category 6 Ethernet Cable with a transmission rate of 1000M, the maximum 

effective transmission distance is 100 meters.

In the integrated wiring specification, it is also clearly required that the horizontal wiring cannot exceed 90 meters, and the total link length cannot exceed 100 meters. In other words, 

100 meters is a limit for wired Ethernet, and this limit is the length of the link from the network card to the hub device.


2. How is the maximum distance of 100 meters obtained?

What caused the 100-meter transmission distance limit of Ethernet Cable? It is necessary to delve into the deep physical principles of Ethernet Cable. The transmission of the network

 is actually the transmission of the network signal on the Ethernet Cable. As an electronic signal, when it is transmitted in the Ethernet Cable, it must be affected by resistance and 

capacitance, which leads to the attenuation and distortion of the network signal. When the signal attenuation or distortion reaches a certain level, it will affect the effective and stable transmission of the signal.


3. Therefore, Ethernet Cable has a transmission distance limit, so how do you calculate the upper limit of 100 meters?

 Category 5 UTP and Category 5 UTP are mainly for computer network services. According to the 100Base-TX regulations of Fast Ethernet, the communication rate is 100mbps. The time it takes for 

100mbps Ethernet to transmit 1 bit of data (also known as "bit time") ) It can be calculated as follows: 1 bit time=1/100mbps=10ns

Data information is transmitted in the network, and when passing through different components, there will be a delay. The delay of the five types of UTP is 5.56ns/m. When designing Ethernet, it is 

required to comply with a relay rule. This rule is also called the golden rule or 5-4-3-2-1 rule. This rule applies not only to 10mbps Ethernet, but also to Fast Ethernet. This rule requires that when the

 ring collision delay should not exceed 512 bits, for a transmission rate of 100mbps, it is 5120ns. In the loop, the network components include cables, relay units, MAU, and DTE. Add their delays and 

multiply them by two to get the loop delay. At the same time, the loop conflict diameter can also be calculated. According to this theory, it is possible to calculate the longest distance that the signal 

can transmit to ensure that a minimum frame is sent. This is why the link span is limited to 100 meters.


When the Ethernet Cable exceeds 100 meters, because the conflict cannot be detected in time, the information packet damaged by the conflict is transmitted and received by the receiver. The

 information packet is forced to be discarded because it fails to pass the verification. At this time, it is retransmitted. The mechanism is not activated, so it will cause packet loss. When the transmission 

rate of the Ethernet Cable is lower than 100 mbps, in practical applications, the length limit of 100 meters can be relaxed for the Ethernet Cable. It must be stated that although this is actually effective,

 it does not meet the standard. In the certification test, it must be explained, otherwise there may be some problems, such as product warranty.