Tips & Definitions:
Communications- The electronic transfer of information from one location to another. "Data communications" or "datacom" refers to digital transmission, and "telecommunications" or "telecom" refers to a mix of voice and data, both analog and digital. "Networking" refers specifically to LANs and WANs. The term "communications" used by itself generally pertains to telecom-related subjects such as PBXs, modems, call centers and the like. However, the word is also a generic English word that is used descriptively such as in the headline "Analog Vs. Digital Communications" below. Thus, "communications" is used specifically in some cases and more generically in others. The Protocol The way data communications systems "talk to" each other is defined in a set of standards called "protocols." Protocols work in a hierarchy starting at the top with the user's program and ending at the bottom with the plugs, sockets and electrical signals. See communications protocol and OSI. Analog Vs. Digital Communications The world's largest communications system is the telephone network, which is a mix of analog and digital communications. The system, which used to be entirely analog and transmitted only voice frequencies is now almost entirely digital. The only analog part is the line between your telephone and a digital conversion point (digital loop carrier) within a mile or so of your house. Analog systems are error prone, because the electronic frequencies get mixed together with unwanted signals (noise) that are nearby. In analog telephone networks, amplifiers were placed in the line every few miles to boost the signal, but they could not distinguish between signal and noise. Thus, the noise was amplified along with the signal. By the time the receiving person or machine got the signal, it may have been impossible to decipher. In a "digital" network, only two (binary) distinct frequencies or voltages are transmitted. Instead of amplifiers, repeaters are used, which analyze the incoming signal and regenerate a new outgoing signal. Any noise on the line is filtered out at the next repeater. When data are made up of only two signals (0 and 1), they can be more easily distinguished from the garble. Digital is simple!
Information Information is a term with many meanings depending on context, but is as a rule closely related to such concepts as meaning, knowledge, instruction, communication, representation, and mental stimulus. Although many people speak of the advent of the "information age," the "information society," and information technologies, and even though information science and computer science are often in the spotlight, the word "information" is often used without careful consideration of the various meanings it has come to acquire. Often information is viewed as a type of input to an organism or designed device. Inputs are of two kinds. Some inputs are important to the function of the organism (for example, food) or device (energy) by themselves. In his book Sensory Ecology, Dusenbery called these causal inputs. Other inputs (information) are important only because they are associated with causal inputs and can be used to predict the occurrence of a causal input at a later time (and perhaps another place). Some information is important because of association with other information but eventually there must be a connection to a causal input. In practice, information is usually carried by weak stimuli that must be detected by specialized sensory systems and amplified by energy inputs before they can be functional to the organism or device. For example, light is often a causal input to plants but provides information to animals. The colored light reflected from a flower is too weak to do much photosynthetic work but the visual system of the bee detects it and the bee's nervous system uses the information to guide the bee to the flower, where the bee often finds nectar or pollen, which are causal inputs, serving a nutritional function. The most important meanings of information are identified in the following sections roughly in order of narrowest to broadest. Information as a message: Information is a message, something to be communicated from the sender to the receiver, as opposed to noise, which is something that inhibits the flow of communication or creates misunderstanding. If information is viewed merely as a message, it does not have to be accurate. It may be a lie, or just a sound of a kiss. This model assumes a sender and a receiver, and does not attach any significance to the idea that information is something that can be extracted from an environment, e.g., through observation or measurement. Information in this sense is simply any message the sender chooses to create.
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