What is a network adapter , where is it located and how does it work? These are the main issues that will be addressed in this article.
Why is it needed?
An adapter is equipment that provides network functionality at the link and physical layers. It is referred to as peripheral devices. It interacts directly with the data medium.
The adapter successfully solves the problem of reliable encryption with binary data on external communication lines. Since it is a computer controller, it carries out its work under the control of a driver installed in the operating system. The network adapter is mounted in the socket of the motherboard. It converts the parallel codes that are used in a computer into a stream of powerful signals that transmit data over a network. Therefore, they are put forward the requirement of compatibility with the network operating system and the information bus of the PC itself. How to install a network adapter in the motherboard?
Customization
We examined what a network adapter is, now we can consider its preparation for work. If it meets the PnP standard, then the configuration is automatic. In another 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 of them:
- Carry out galvanic isolation with twisted pair or coaxial cable. Basically, pulse transformers are used for this purpose, although the use of optocouplers is also possible.
- Transmission (reception) of data. They come from RAM to the adapter or from it to the computer's memory thanks to the input / output and direct access channels.
- Buffering. It is used to coordinate the speed of data transfer from or to the adapter with how they are transmitted over the network. Also, during information processing, it is stored in a buffer. It allows the adapter to work with the entire information package. Also, thanks to the adapter, the data processing speeds of the various components of the LAN are matched to each other.
- The formation of the package. The network adapter data must be divided into separate blocks in the transmission mode (or they are collected at reception), then to design them as a frame of a certain format. It will be composed of several service fields, where the address of the recipient's computer is indicated, as well as the checksum of the frame, by which the device receives a conclusion about whether the delivered information is correct.
- Access to the communication channel. Also in his "jurisdiction" is a set of rules by which you can get the opportunity to work with the transmission medium. In addition, the adapter detects conflict situations and monitors the status of the network.
- Identification of your address in the packet that is accepted. It can be determined by the installation of switches, flashed in the ROM, or stored in a special register.
- Convert the parallel code to serial when transmitting data, and it performs their reverse conversion when they are received. There is a slight exception to this. When the data transfer mode is active, then information is transmitted in a serial code over the communication channel.
- Encoding / decoding data. At this stage, electrical signals are generated that are used to represent information. In most cases, Manchester coding is used. This method does not require a synchronization signal to be transmitted in order to recognize units and zeros. In this case, polarity reversal is used.
- Reception or transmission of data pulses.
Also, network adapters, when working with the necessary software, can recognize and process an error that occurs due to poor equipment operation, collisions or electrical interference.
Base address
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 protocol and environment access methods
Network technology uses three main types of adapter:
- Ethernet
- FDDI
- 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 data transmission media.
For example, Ethernet works with:
- Fiber optic cable.
- Unshielded twisted pair.
- Coaxial cable.
When a device must work with an environment for which it was not originally intended, converters and transceivers are used. Network adapters are also distinguished by the internal data bus:
- PCI
- EISA
- ISA
- MCA
By what parameters can network adapters be classified?
In addition to the above, the following can also be used:
- Type of tire.
- The amount of buffer for the packet.
- Transmission speed.
- Compatible with different microprocessors.
- Tire performance.
- By the presence / absence of the use of direct access to memory.
- Connector design.
- Addressing I / O ports and interrupt requests.
Physical implementation
Let's take an example of a network adapter for Windows 7. For the most part, they can be placed on the motherboard. But here the TP-Link network adapter is outside the boundaries of the system unit.
This is not least due to its functionality (the ability to connect multiple computers and create a Wi-Fi network, that is, it also acts as a router and router). The latter option allows the adapter to create even a small local area network, which combines all devices with the necessary interface within reach. You can also come across a USB network adapter. It is usually offered to people by mobile network operators. The USB network adapter in this case looks like a USB flash drive, and it connects in the same way. For data transfer, 2G or 3G Internet is used. Here in what ways can we see a network adapter for Windows 7. By the way, how is this device implemented in laptops? If we talk about the Asus network adapter, 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 ones, 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 examined an example of creating a local network with their help. In conclusion, it is worth saying 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 transitional gateway.