Communications Channels: It is a pathway over which information can be communicated. It might be stated by a physical wire which connects communicating devices, or through radio, laser, or other radiated energy source which has no obvious physical presence. Information sent via a communications channel has a source from which information begins, and a destination to which the information is conveyed. Though information begins from a single source, there might be more than one destination, depending upon how many receive stations are associated to the channel and how much energy the transmitted signal holds.
In digital communications channel, the information is symbolized by individual data bits that might be encapsulated into multibit message units. The byte, which comprises of eight bits, is an illustration of a message unit which might be conveyed via a digital communications channel. The collection of bytes might itself be grouped into a frame or other higher-level message unit. These multiple levels of encapsulation ease the handling of messages in the complex data communications network.