What is a network adapter? What is a LAN Adapter?

What is a network adapter, where is it located and how does it work? Here are the main questions that will be studied in this article.

Why is it necessary?

An adapter is an equipment that providesthe functioning of the network at the channel and physical levels. He is referred to peripheral devices. It directly interacts with the data transmission medium.

The adapter successfully solves the problem of reliable exchangebinary data on external lines of communication. Since it is a computer controller, its work is carried out under the control of the driver installed in the operating system. The network adapter in the motherboard socket is also mounted. It converts the parallel codes that are used in the computer to a stream of powerful signals that transmit data over the network. Therefore, they are required to be compatible with the network operating system and the information bus of the PC itself. How to install the network adapter in the motherboard?

Customize

We figured out what a network adapter is, nowyou can also consider its preparation for work. If it meets the PnP standard, then the setting is automatic. In the other case, you must manually work with the interrupt request line and the I / O address.

Functions

We examined what a network adapter is and how it is configured, and now let's talk about the tasks that are solved when sending or receiving messages. There are nine in all:

1. Carry out a galvanic isolation with a twisted pair or coaxial cable. In general, pulse transformers are used for this purpose, although the use of an optocoupler is also possible.
2. Transmission (reception) of data. They come from RAM to the adapter or from it to the computer memory thanks to the input / output channels and direct access.
3. Buffering. It is used to match the speed of data transfer from or to the adapter with how it is transmitted over the network. Also, during the processing of information, it is stored in a buffer. It allows the adapter to work with the entire package of information. Also, thanks to the adapter, the processing speeds of the various LAN components are coordinated among themselves.
4. Formation of the package. The network adapter data must be divided into separate blocks in the transmission mode (or they are collected at the reception), then to draw them as a frame of a certain format. It will be made up of several service fields, where the address of the recipient's computer is specified, as well as the checksum of the frame by which the device receives a conclusion as to whether the delivered information is correct.
5. Access to the communication channel. Also in his "jurisdiction" is a set of rules, with which you can get the ability to work with the transmission medium. In addition, the adapter identifies conflict situations and monitors the network status.
6. Identify your address in the package that is accepted. It can be determined by the setting of switches, stitched in PROM or stored in a special register.
7. Convert the parallel code tosequential in the transmission of data, and it conducts their reverse conversion when they are received. From this there is a small exception. When the data transfer mode is active, information is transmitted on the communication channel in a serial code.
8. Encoding / decoding of data. At this stage, electrical signals are generated that are used to represent information. In most cases, Manchester encoding is used. This method does not require that a synchronizing signal be transmitted to recognize units and zeros. In this case, polarity reversal is used.
9. Receiving or transmitting data pulses.

Also, network adapters, when working with the necessary software, can recognize and process an error that arises from poor equipment performance, collisions, or electrical interference.

Base address

It is also called physical. Some network adapters can use the computer's RAM as a buffer to store outgoing and incoming data packets.

The base address in this case is a hexadecimal number that indicates where the information is located.

Classification by methods of access to protocols and environment

In network technology, there are three main types of adapter:

1. Ethernet.
2. FDDI.
3. Token Ring.

Usually a certain model works only on its own network technology. But at the same time they can support, as a rule, several different media.

For example, Ethernet works with:

1. Fiber optic cable.
2. Unshielded twisted pair.
3. Coaxial cable.

When the device should work with an environment for which it was not originally intended, then converters and transceivers are used. Also, network adapters are distinguished on the internal data bus:

1. PCI.
2. EISA.
3. ISA.
4. MCA.

By what parameters can the network adapters be classified?

In addition to the above, the following can also be used:

1. Type of tire.
2. Volume of the buffer for the package.
3. Transmission speed.
4. Compatibility with different microprocessors.
5. Speed ​​of the tire.
6. By the presence / absence of using direct memory access.
7. Connector design.
8. Addressing the output / input ports and interrupt requests.

Physical realization

Let's look at the network as an exampleadapter for Windows 7. In the mass of their they can be placed on the motherboard. But here the TP-Link network adapter is banned from the boundaries of the system unit.

This is not least due to hisfunctionality (the ability to connect multiple computers and create a Wi-Fi network, that is, it also acts as a router and router). The latter possibility allows you to create an adapter, even a small local network, which combines all the devices with the necessary interface within the radius of availability. You can also find a USB network adapter. It is, as a rule, offered to people by mobile network operators. The network USB adapter in this case looks like a USB flash drive, and it connects the same way. For data transmission, 2G or 3G internet is used. Here in what hypostases before us can appear the network adapter for Windows 7. By the way, and how this device is implemented in laptops? If we talk about the network adapter Asus, then it must be present in the devices. The same applies to other laptops. The fact is that they are designed for use in various conditions, including mobile, when you have to work with everything in a row.

Conclusion

So, we found out what a network adapter is, what types they are and how they are implemented in practice.

We also considered an example of creating a localnetworks with their help. In conclusion, it should be said that they can be found not only on home computers or laptops, but also on the servers of providers that provide Internet access to their users. Only here they are used as a gateway.