communication channel - it is an integral part of every system of information transmission.In general, this term is hidden set of devices that are designed to provide a broadcast signal with defined properties from one point to another.
The link contains a very important part, as a line of communication by which the transmission of electromagnetic waves directed from the transmitter to the receiver.What does it mean?One channel may generally comprise a number of lines.You could say the opposite point.Typically, the same link simultaneously included in the composition of a number of channels.But that is not all.In addition to the lines of the channels include equipment that is mounted on the intermediate and end points.Depending on the task the same apparatus can belong to different elements.
Classification of channels carried on different grounds: the nature of technical signals, the appointment system used lines, as well as other parameters.
There is another distinction.The communication link can be analog or digital, and may create both on the same link.At the same time they function separately.This is realized by means of several possibilities.The new systems are replaced with active analog channels to digital.But it is not a prerequisite.The toll network, most of them over the entire length, usually analog, however, there are analog-to-digital.Therefore, the signal will be partly held as an analog, and partly - as a digital.
formation of different channels on a pair of wires signalers made since the twenties of the last century.According to one of the coaxial line can be transmitted to 10800 voice channels or digital signal whose rate is 565 megabits per second.Here and should talk about the main differences between these concepts.On the line we can not say that it has a certain capacity as long as will be discussed all the details of its construction, the length and structure of the guide.In that case, if we consider the communication channel, all the characteristics defined.After all, they are usually standardized and are described in great detail, and the type of absolutely nothing depends on nothing.To some extent, the communication line is similar to the railway, and the channel in this case is comparable with the carriage, which is clearly given load.
There is another concept.The dedicated channel is an element with a fixed bandwidth and capacity, which constantly connects a pair of subscribers.Subscribers may make individual devices or entire networks.This type is usually rented from companies and big corporations can pave your own.
communication channel may be analog or digital, and it is selected depending on what needs to test the subscriber.In the case of "vydelenka" company is focused on a certain level of needs.For the organization of the channels used by different lines.
