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Hello everyone, in this lesson we will briefly introduce the network card

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The network card is the device used by the mainboard to connect to the network.

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Common network cards include wired network cards and wireless network cards.

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At the same time, these network cards can also be divided into USB network cards,

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PCIE network cards and onboard network cards according to the connection mode with the mainboard.

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What we are talking about here is mainly the onboard network card

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Other USB network cards and PCIE network cards are pluggable and replaceable,

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which is not within the scope of our discussion

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The onboard network card, like the sound card, generally exists on the mainboard in the form of a chip.

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It is generally on the left side of the mainboard, and is closer to the network cable interface.

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And the onboard network card has one of the biggest features,

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that is, there is a crystal oscillator around the network card.

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This crystal oscillator is 25M

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When we look for the network card in the mainboard, we are actually looking for this crystal oscillator

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After finding the crystal oscillator, we found the network card chip

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Let's introduce the NIC interface

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The network card interface is also called the RJ45 interface, which is used to connect the crystal head

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The RJ45 interface generally includes 8 pins and 2 indicator lights

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When the crystal head is connected, the two indicators will light up

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Different colors represent different meanings

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Most of the RJ45 ports on the mainboard now have built-in network transformers, which is the one on the right

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This network transformer is also called a network bridge or a data pump.

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It mainly plays the role of enhancing the signal, repairing the signal and isolating high voltage in the circuit.

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And this network transformer also has a certain lightning protection function.

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It is precisely because of the existence of the network transformer

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that the shrapnel in the middle of the RJ45 interface cannot communicate with the pins below.

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Because there is a network transformer in the middle

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However, although the pins are blocked, the data can be transmitted completely.

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The above is a brief introduction to the network card