The communication channel and its structure

The communication channel is an integral part of every information transmission system . In general, this concept hides a set of devices that are designed to ensure the transmission of a signal with certain properties from one point to another.

The communication channel contains such an important detail as the communication line through which the transmission of electromagnetic oscillations directed from the transmitter to the receiving device is carried out. What does it mean? One channel in general can contain a number of lines. You can say about the opposite moment. Usually, the same communication line enters simultaneously into a number of channels. But that is not all. In addition to the lines, the channels include equipment that is mounted at intermediate and final points. Depending on the task, the same devices can refer to different elements.

Classification of communication channels is carried out on different grounds: the technical nature of the signals, the purpose of the system, the lines used, and other parameters.

There is another distinction. The communication channel can be analog or digital, and the creation of both is possible on the same communication line. In doing so, they function separately. This is realized through several possibilities. In new systems, analog channels are actively being replaced with digital ones. But this is not a prerequisite. In the long-distance network, most of them along the entire length, as a rule, are analog, but there are also analog-digital ones. Therefore, in part the signal will pass as analog, and partly as digital.

The formation of different channels on a pair of wires by signalmen has been made since the twenties of the last century. One coaxial line can transmit up to 10,800 telephone channels, or a digital signal, whose speed is 565 megabits per second. Here we should talk about the main differences between these concepts. On the line, one can not say that it has a certain bandwidth until it is told about all the details of its construction, length, and also the structural guide. And in the case when we consider the communication channel, all the characteristics are given. After all, they are usually standardized and described in great detail, and their type is completely independent of anything. To a certain extent, the communication line is similar to the railway, and the channel in this case is comparable with a car with a clearly defined load capacity.

There is one more concept. The dedicated communication channel is an element with a fixed bandwidth and bandwidth, which permanently connects a pair of subscribers. Subscribers can be individual devices or entire networks. This type is usually leased from companies, and large corporations can build their own.

The communication channel can be analog or digital, and it is selected depending on what needs the subscriber is experiencing. In the case of "vydelenki" the company is guided by a certain level of needs. For the organization of channels different lines are used.