Data and communication

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Data and communication

Next Topic TOC The distance over which data moves within a computer may vary from a few thousandths of an inch, as is the case within a single IC chip, to as much as several feet along the backplane of the main circuit board.

Over such small distances, digital data may be transmitted as direct, two-level electrical signals over simple copper conductors. Except for the fastest computers, circuit designers are not very concerned about the shape of the conductor or the analog characteristics of signal transmission.

Frequently, however, data must be sent beyond the local circuitry that constitutes a computer. In many cases, the distances involved may be enormous. Unfortunately, as the distance between the source of a message and its destination increases, accurate transmission becomes increasingly difficult.

This results from the electrical distortion of signals traveling through long conductors, and from noise added to the signal as it propagates through a transmission medium. In this case, distortion and noise can become so severe that information is lost.

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Data Communications concerns the transmission of digital messages to devices external to the message source. As a rule, the maximum permissible transmission rate of a message is directly proportional to signal power, and inversely proportional to channel noise.

It is the aim of any communications system to provide the highest possible transmission rate at the lowest possible power and with the least possible noise.

It may be defined by a physical wire that connects communicating devices, or by a radio, laser, or other radiated energy source that has no obvious physical presence. Information sent through a communications channel has a source from which the information originates, and a destination to which the information is delivered.

Although information originates from a single source, there may be more than one destination, depending upon how many receive stations are linked to the channel and how much energy the transmitted signal possesses.

In a digital communications channel, the information is represented by individual data bits, which may be encapsulated into multibit message units. A byte, which consists of eight bits, is an example of a message unit that may be conveyed through a digital communications channel.

A collection of bytes may itself be grouped into a frame or other higher-level message unit. Such multiple levels of encapsulation facilitate the handling of messages in a complex data communications network.

Data and communication

Any communications channel has a direction associated with it: The message source is the transmitter, and the destination is the receiver. A channel whose direction of transmission is unchanging is referred to as a simplex channel.

For example, a radio station is a simplex channel because it always transmits the signal to its listeners and never allows them to transmit back. A half-duplex channel is a single physical channel in which the direction may be reversed. Messages may flow in two directions, but never at the same time, in a half-duplex system.

In a telephone call, one party speaks while the other listens.

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After a pause, the other party speaks and the first party listens. Speaking simultaneously results in garbled sound that cannot be understood. A full-duplex channel allows simultaneous message exchange in both directions. It really consists of two simplex channels, a forward channel and a reverse channel, linking the same points.

The transmission rate of the reverse channel may be slower if it is used only for flow control of the forward channel. Because it is neither practical nor economic to transfer all bits of a long message simultaneously, the message is broken into smaller parts and transmitted sequentially.

Bit-serial transmission conveys a message one bit at a time through a channel. Each bit represents a part of the message. The individual bits are then reassembled at the destination to compose the message.

In general, one channel will pass only one bit at a time. Thus, bit-serial transmission is necessary in data communications if only a single channel is available. Bit-serial transmission is normally just called serial transmission and is the chosen communications method in many computer peripherals.

Byte-serial transmission conveys eight bits at a time through eight parallel channels.Data communication is the transmission of digital messages to external devices. If you look around your house, you will see many examples of data communication at work.

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Your. Solutions. IDCS's Custom Software Development Team is committed to creating logical software solutions. SaaS, or Software as a Service, describes any service where consumers are able to access software applications over the internet.

Data communications (DC) is the process of using computing and communication technologies to transfer data from one place to another, and vice versa.

It enables the movement of electronic or digital data between two or more nodes, regardless of geographical location, technological medium or data contents. UNdata is an internet-based data service which brings UN statistical databases within easy reach of users through a single entry point ( from.

The Hazard Communication Standard (HCS) (29 CFR (g)), revised in , requires that the chemical manufacturer, distributor, or importer provide Safety Data Sheets (SDSs) (formerly MSDSs or Material Safety Data Sheets) for each hazardous chemical to downstream users to communicate.

Nonviolent Communication (NVC) is based on the principles of nonviolence-- the natural state of compassion when no violence is present in the heart.

Data transmission - Wikipedia