In communications and information processing, code is a system of rules to convert information—such as a letter, word, sound, image, or gesture—into another form, sometimes shortened or secret, for communication through a communication channel or storage in a storage medium. An early example is an invention of language, which enabled a person, through speech, to communicate what they thought, saw, heard, or felt to others. But speech limits the range of communication to the distance a voice can carry and limits the audience to those present when the speech is uttered. The invention of writing, which converted spoken language into visual symbols, extended the range of communication across space and time.
In information theory and coding theory with applications in computer science and telecommunication, error detection and correction (EDAC) or error control are techniques that enable reliable delivery of digital data over unreliable communication channels. Many communication channels are subject to channel noise, and thus errors may be introduced during transmission from the source to a receiver. Error detection techniques allow detecting such errors, while error correction enables reconstruction of the original data in many cases.
Signals intelligence (SIGINT) is intelligence-gathering by interception of signals, whether communications between people or from electronic signals not directly used in communication. Signals intelligence is a subset of intelligence collection management. As classified and sensitive information is usually encrypted, signals intelligence in turn involves the use of cryptanalysis to decipher the messages. Traffic analysis—the study of who is signaling whom and in what quantity—is also used to integrate information again.
A communication channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used for information transfer of, for example, a digital bit stream, from one or several senders to one or several receivers. A channel has a certain capacity for transmitting information, often measured by its bandwidth in Hz or its data rate in bits per second.
Within the realm of communication studies, organizational communication is a field of study surrounding all areas of communication and information flow that contribute to the functioning of an organization. Organizational communication is constantly evolving and as a result, the scope of organizations included in this field of research have also shifted over time. Now both traditionally profitable companies, as well as NGO's and non-profit organizations, are points of interest for scholars focused on the field of organizational communication. Organizations are formed and sustained through continuous communication between members of the organization and both internal and external sub-groups who possess shared objectives for the organization. The flow of communication encompasses internal and external stakeholders and can be formal or informal.
Communication theory is a proposed description of communication phenomena, the relationships among them, a storyline describing these relationships, and an argument for these three elements. Communication theory provides a way of talking about and analyzing key events, processes, and commitments that together form communication. Theory can be seen as a way to map the world and make it navigable; communication theory gives us tools to answer empirical, conceptual, or practical communication questions.
Communications management is the systematic planning, implementing, monitoring, and revision of all the channels of communication within an organization and between organizations. It also includes the organization and dissemination of new communication directives connected with an organization, network, or communications technology. Aspects of communications management include developing corporate communication strategies, designing internal and external communications directives, and managing the flow of information, including online communication. It is a process that helps an organization to be systematic as one within the bounds of communication.
Coding theory is the study of the properties of codes and their respective fitness for specific applications. Codes are used for data compression, cryptography, error detection and correction, data transmission and data storage. Codes are studied by various scientific disciplines—such as information theory, electrical engineering, mathematics, linguistics, and computer science—for the purpose of designing efficient and reliable data transmission methods. This typically involves the removal of redundancy and the correction or detection of errors in the transmitted data.
Two-way communication is a form of transmission in which both parties involved transmit information. Two-way communication has also been referred to as interpersonal communication. Common forms of two-way communication are:
Sender Policy Framework (SPF) is an email authentication method which ensures the sending mail server is authorized to originate mail from the email sender's domain. This authentication only applies to the email sender listed in the "envelope from" field during the initial SMTP connection. If the email is bounced, a message is sent to this address, and for downstream transmission it typically appears in the "Return-Path" header. To authenticate the email address which is actually visible to recipients on the "From:" line, other technologies such as DMARC must be used. Forgery of this address is known as email spoofing, and is often used in phishing and email spam.
Marketing communications refers to the use of different marketing channels and tools in combination. Marketing communication channels focus on how businesses communicate a message to its desired market, or the market in general. It is also in charge of the internal communications of the organization. Marketing communication tools include advertising, personal selling, direct marketing, sponsorship, communication, public relations, social media, customer journey and promotion.
In computer science, message passing is a technique for invoking behavior on a computer. The invoking program sends a message to a process and relies on that process and its supporting infrastructure to then select and run some appropriate code. Message passing differs from conventional programming where a process, subroutine, or function is directly invoked by name. Message passing is key to some models of concurrency and object-oriented programming.
In data communications, flow control is the process of managing the rate of data transmission between two nodes to prevent a fast sender from overwhelming a slow receiver. Flow control should be distinguished from congestion control, which is used for controlling the flow of data when congestion has actually occurred. Flow control mechanisms can be classified by whether or not the receiving node sends feedback to the sending node.
Decoding, in semiotics, is the process of interpreting a message sent by an addresser (sender) to an addressee (receiver). The complementary process – creating a message for transmission to an addressee – is called encoding.
Economic noise, or simply noise, describes a theory of pricing developed by Fischer Black. Black describes noise as the opposite of information: hype, inaccurate ideas, and inaccurate data. His theory states that noise is everywhere in the economy and we can rarely tell the difference between it and information.
The Shannon–Weaver model is one of the first and most influential models of communication. It was initially published in the 1948 paper A Mathematical Theory of Communication and explains communication in terms of five basic components: a source, a transmitter, a channel, a receiver, and a destination. The source produces the original message. The transmitter translates the message into a signal, which is sent using a channel. The receiver translates the signal back into the original message and makes it available to the destination. For a landline phone call, the person calling is the source. They use the telephone as a transmitter, which produces an electric signal that is sent through the wire as a channel. The person receiving the call is the destination and their telephone is the receiver.
Information is an abstract concept that refers to that which has the power to inform. At the most fundamental level, information pertains to the interpretation of that which may be sensed, or their abstractions. Any natural process that is not completely random and any observable pattern in any medium can be said to convey some amount of information. Whereas digital signals and other data use discrete signs to convey information, other phenomena and artifacts such as analogue signals, poems, pictures, music or other sounds, and currents convey information in a more continuous form. Information is not knowledge itself, but the meaning that may be derived from a representation through interpretation.
Models of communication are simplified representations of the process of communication. Most models try to describe both verbal and non-verbal communication and often understand it as an exchange of messages. Their function is to give a compact overview of the complex process of communication. This helps researchers formulate hypotheses, apply communication-related concepts to real-world cases, and test predictions. Despite their usefulness, many models are criticized based on the claim that they are too simple because they leave out essential aspects. The components and their interactions are usually presented in the form of a diagram. Some basic components and interactions reappear in many of the models. They include the idea that a sender encodes information in the form of a message and sends it to a receiver through a channel. The receiver needs to decode the message to understand the initial idea and provides some form of feedback. In both cases, noise may interfere and distort the message.
The source–message–channel–receiver model is a linear transmission model of communication. It is also referred to as the sender–message–channel–receiver model, the SMCR model, and Berlo's model. It was first published by David Berlo in his 1960 book The Process of Communication. It contains a detailed discussion of the four main components of communication: source, message, channel, and receiver. Source and receiver are usually distinct persons but can also be groups and, in some cases, the same entity acts both as source and receiver. Berlo discusses both verbal and non-verbal communication and sees all forms of communication as attempts by the source to influence the behavior of the receiver. The source tries to achieve this by formulating a communicative intention and encoding it in the form of a message. The message is sent to the receiver using a channel and has to be decoded so they can understand it and react to it. The efficiency or fidelity of communication is defined by the degree to which the reaction of the receiver matches the purpose motivating the source.
Schramm's model of communication is an early and influential model of communication. It was first published by Wilbur Schramm in 1954 and includes innovations over previous models, such as the inclusion of a feedback loop and the discussion of the role of fields of experience. For Schramm, communication is about sharing information or having a common attitude towards signs. His model is based on three basic components: a source, a destination, and a message. The process starts with an idea in the mind of the source. This idea is then encoded into a message using signs and sent to the destination. The destination needs to decode and interpret the signs to reconstruct the original idea. In response, they formulate their own message, encode it, and send it back as a form of feedback. Feedback is a key part of many forms of communication. It can be used to mitigate processes that may undermine successful communication, such as external noise or errors in the phases of encoding and decoding.
