If the wireless network cannot be received after updating the driver, it can be judged that the wireless network card is broken. If the wireless network can still receive the updated driver, it is a driver problem.
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network card
This entry is compiled and applied by the scientific entry "Popular Science China"? Review.
The network card is a network component working in the link layer, and it is the interface connecting computers and transmission media in the local area network. It can not only realize the physical connection and electrical signal matching with transmission media in LAN, but also involve the functions of sending and receiving frames, encapsulating and unpacking frames, media access control, data encoding and decoding, data caching and so on.
brief introduction
The connection between the computer and the external LAN is realized by inserting the network interface board into the main chassis (or inserting the PCMCIA card into the notebook computer). Network interface board is also called communication adapter or network adapter or network interface card (NIC), but more people prefer to use the simpler name "NIC".
Functional interpretation
The network card is equipped with a processor and memory (including RAM and ROM). The communication between network card and LAN is realized by serial transmission of cable or twisted pair. The communication between the network card and the computer is carried out through parallel transmission of I/O bus on the computer motherboard. Therefore, an important function of the network card is serial/parallel conversion. Because the data rate on the network is different from that on the computer bus, a memory chip for caching data must be installed in the network card.
When installing a network card, the device driver that manages the network card must be installed in the operating system of the computer. This driver will tell the network card where to store the data blocks transmitted by the LAN later. The network card should also be able to implement the Ethernet protocol.
The network card is not an independent autonomous unit, because the network card itself has no power supply, and it must use the power supply of the inserted computer and be controlled by the computer. Therefore, the network card can be regarded as a semi-autonomous unit. When the network card receives an erroneous frame, it will discard the frame without informing the computer it is plugged into. When the network card receives a correct frame, it notifies the computer with an interrupt and transmits it to the network layer in the protocol stack. When the computer wants to send an IP packet, it is transmitted to the network card from the protocol stack, assembled into a frame and sent to the LAN.
With the continuous improvement of integration, the number of chips on the network card is getting less and less. Although there are many types of network cards produced by various manufacturers, their functions are similar? [ 1]? .
strong function
1, data encapsulation and decapsulation
When sending, the data handed over by the previous layer is added with header and trailer to form an Ethernet frame. When receiving, the Ethernet frame is stripped of its head and tail, and then sent to the upper layer.
2. Link management
This paper mainly studies the implementation of CSMA/CD (Carrier Sense Multiple Access with Collision Detection) protocol.
3. Coding and decoding
Manchester coding and decoding.
Source: Baidu Encyclopedia-Network Card