The transmission of words, sounds, images, or data in the form of electronic or electromagnetic signals or impulses. Transmission media include the telephone (using wire or optical cable), radio, television, microwave, and satellite. Data communication, the fastest growing field of telecommunication, is the process of transmitting data in digital form by wire or radio.
Digital data can be generated directly in a 1/0 binary code by a computer or can be produced from a voice or visual signal by a process called encoding. A data communications network is created by interconnecting a large number of information sources so that data can flow freely among them. The data may consist of a specific item of information, a group of such items, or computer instructions. Examples include a news item, a bank transaction, a mailing address, a letter, a book, a mailing list, a bank statement, or a computer program.
The devices used can be computers, terminals (devices that transmit and receive information), and peripheral equipment such as printers (see Computer; Office Systems). The transmission line used can be a normal or a specially purchased telephone line called a leased, or private, line (see Telephone). It can also take the form of a microwave or a communications-satellite linkage, or some combination of any of these various systems.
Hardware and Software
Each telecommunications device uses hardware, which connects a device to the transmission line; and software, which makes it possible for a device to transmit information through the line.
Hardware usually consists of a transmitter and a cable interface, or, if the telephone is used as a transmission line, a modulator/demodulator, or modem.
A transmitter prepares information for transmission by converting it from a form that the device uses (such as a clustered or parallel arrangement of electronic bits of information) to a form that the transmission line uses (such as, usually, a serial arrangement of electronic bits). Most transmitters are an integral element of the sending device.
A cable interface, as the name indicates, connects a device to a cable. It converts the transmitted signals from the form required by the device to the form required by the cable. Most cable interfaces are also an integral element of the sending device.
A modem converts digital signals to and from the modulated form required by the telephone line to the demodulated form that the device itself requires. Modems transmit data through a telephone line at various speeds, which are measured in bits per second (bps) or as signals per second (baud). Modems can be either integral or external units. An external unit must be connected by cable to the sending device. Most modems can dial a telephone number or answer a telephone automatically.
Among the different kinds of software are file-transfer, host, and network programs. File-transfer software is used to transmit a data file from one device to another. Host software identifies a host computer as such and controls the flow of data among devices connected to it. Network software allows devices in a computer network to transmit information to one another.
Three major categories of telecommunication applications can be discussed here: host-terminal, file-transfer, and computer-network communications.
In these types of communications, one computer-the host computer-is connected to one or more terminals. Each terminal transmits data to or receives data from the host computer. For example, many airlines have terminals that are located at the desks of ticket agents and connected to a central, host computer. These terminals obtain flight information from the host computer, which may be located hundreds of kilometers away from the agent's site.
The first terminals to be designed could transmit data only to or from such host computers. Many terminals, however, can now perform other functions such as editing and formatting data on the terminal screen or even running some computer programs. Manufacturers label terminals as "dumb," "smart," or "intelligent" according to their varying capabilities. These terms are not strictly defined, however, and the same terminal might be labeled as dumb, smart, or intelligent depending upon who is doing the labeling and for what purposes.
In file-transfer communications, two devices are connected: either two computers, two terminals, or a computer and a terminal. One device then transmits an entire data or program file to the other device. For example, a person who works at home might connect a home computer to an office computer and then transmit a document stored on a diskette to the office computer.
An outgrowth of file transfer is electronic mail. For example, an employee might write a document such as a letter, memorandum, or report on a computer and then send the document to another employee's computer.
In computer-network communications, a group of devices is interconnected so that the devices can communicate and share resources. For example, the branch-office computers of a company might be interconnected so that they can route information to one another quickly. A company's computers might also be interconnected so that they can all share the same hard disk.
The three kinds of computer networks are local area networks (LAN), private branch exchange (PBX) networks, and wide-area networks (WAN). LANs interconnect devices with a group of cables; the devices communicate at a high speed and must be in close proximity. A PBX network interconnects devices with a telephone switching system; in this kind of network, the devices must again be in close proximity. In wide-area networks, on the other hand, the devices can be at great distances from one another; such networks usually interconnect devices by means of telephone.
Public telecommunication services are a relatively recent development in telecommunications. The four kinds of services are network, information-retrieval, electronic-mail, and bulletin-board services.
A public network service leases time on a WAN, thereby providing terminals in other cities with access to a host computer. Examples of such services include Telenet, Tymnet, Uninet, and Datapac. These services sell the computing power of the host computer to users who cannot or do not wish to invest in the purchase of such equipment.
An information-retrieval service leases time on a host computer to customers whose terminals are used to retrieve data from the host. An example of this is CompuServe, whose host computer is accessed by means of the public telephone system. This and other such services provide general-purpose information on news, weather, sports, finances, and shopping.
Other information-retrieval services may be more specialized. For example, Dow Jones News Retrieval Services provide general-purpose information on financial news and quotations, corporate-earning estimates, company disclosures, weekly economic survey updates, and Wall Street Journal highlights. Newsnet provides information from about 200 newsletters in 30 different industries; Dialog Information Services, BRS Bibliographic Retrieval Services, and Orbit Information Retrieval Services provide library information; and Westlaw provides legal information to its users. See Database.
By means of electronic mail, terminals transmit documents such as letters, reports, and telexes to other computers or terminals. To gain access to these services, most terminals use a public network. Source Mail (available through The Source) and EMAIL (available through CompuServe) enable terminals to transmit documents to a host computer. The documents can then be retrieved by other terminals. MCI Mail Service and the U.S. Postal ECOM Service (also available through The Source) let terminals transmit documents to a computer in another city. The service then prints the documents and delivers them as hard copy. ITT Timetran, RCA Global Communications, and Western Union Easylink let terminals send telexes to other cities.
By means of a bulletin board, terminals are able to facilitate exchanges and other transactions. Many bulletin boards do not charge a fee for their services. Users of these services simply exchange information on hobbies, buy and sell goods and services, and exchange computer programs.
Certain telecommunication methods have become standard in the telecommunications industry as a whole, because if two devices use different standards they are unable to communicate properly. Standards are developed in two ways: (1) the method is so widely used that it comes to dominate; (2) the method is published by a standard-setting organization. The most important organization in this respect is the International Telecommunication Union, a specialized agency of the United Nations, and one of its operational entities, the International Telegraph and Telephone Consultative Committee (CCITT). Other organizations in the area of standards are the American National Standards Institute, the Institute of Electrical Engineers, and the Electronic Industries Association. One of the goals of these organizations is the full realization of the integrated services digital network (ISDN), which is projected to be capable of transmitting through a variety of media and at very high speeds both voice and nonvoice data around the world in digital form.
Other developments in the industry are aimed at increasing the speed at which data can be transmitted. Improvements are being made continually in modems and in the communications networks. Some public data networks support transmission of 56,000 bits per second (bps), and modems for home use (see Microcomputer) are capable of as much as 28,800 bps.
When a handful of American scientists installed the first node of a new computer network in the late 60's, they could not know by any chance what phenomenon they had launched. They were set a challenging task to develop and realise a completely new communication system that would be either fully damage-resistant or at least functional even if an essential part of it was in ruins, in case the Third World War started. The scientists did what they had been asked to. By 1972 there were thirty-seven nodes already installed and ARPANET (Advanced Research Projects Agency NET), as the system of the computer nodes was named, was working (Sterling 1993). Since those "ancient times", during which the network was used only for national academic and military purposes (Sterling 1993), much of the character of the network has changed. Its today users work in both commercial and non-commercial branches and not just in academic and governmental institutions. Nor is the network only national: it has expanded to many countries around the world, the network has become international and in that way it got its name. People call it Internet.
The popularity of this new phenomenon is rising rapidly, almost beyond belief. In January 1994 there were an estimated 2 million computers linked to the Internet. However, this is nothing compared to the number from last year's statistics. At the end of 1995, 10 million computers with 40-50 million users were assumed to be connected to the network-of-networks. If it goes on like this, most personal computers will be wired to the network at the end of this century (Internet Society 1996).
The Internet is phenomenal in many ways. One of them is that it connects people from different nations and cultures. The network enables them to communicate, exchange opinions and gain information from one another. As each country has its own national language, in order to communicate and make themselves understood in this multilingual environment the huge number Internet users need to share a knowledge of one particular language, a language that would function as a lingua franca. On the Internet, for various reasons, the lingua franca is English.
Because of the large number of countries into which the Internet has spread and which bring with
them a considerable variety of languages English, for its status of a global language, has become a necessary communication medium on the Internet. What is more, the position of English as the language of the network is strengthened by the explosive growth of the computer web as great numbers of new users are connecting to it every day.
Internet, in computer science, an open interconnection of networks that enables connected computers to communicate directly. There is a global, public Internet and many smaller-scale, controlled-access internets, known as enterprise internets. In early 1995 more than 50,000 networks and 5 million computers were connected via the Internet, with a computer growth rate of about 9 percent per month.
The public Internet supports thousands of operational and experimental services. Electronic mail (e-mail) allows a message to be sent from one computer to one or more other computers. Internet e-mail standards have become the means of interconnecting most of the world's e-mail systems. E-mail can also be used to create collaborative groups through the use of special e-mail accounts called reflectors, or exploders. Users with a common interest join a mailing list, or alias, and this account automatically distributes mail to all its members.
The World Wide Web allows users to create and use point-and-click hypermedia presentations. These documents are linked across the Internet to form a vast repository of information that can be browsed easily.
Gopher allows users to create and use computer file directories. This service is linked across the Internet to allow other users to browse files.
File Transfer Protocol (FTP) allows users to transfer computer files easily between host computers. This is still the primary use of the Internet, especially for software distribution, and many public distribution sites exist.
The Usenet service allows users to distribute news messages automatically among thousands of structured newsgroups. Telnet allows users to log in to another computer from a remote location. Simple Network Management Protocol (SNMP) allows almost any Internet object to be remotely monitored and controlled.
Internets are constructed using many kinds of electronic transport media, including optical fiber, telephone lines, satellite systems, and local area networks. They can connect almost any kind of computer or operating system, and they are self-aware of their capabilities. An internet is usually implemented using international standards collectively called Transmission Control Protocol/Internet Protocol (TCP/IP). The protocols are implemented in software running on the connected computer. Most computers connected to the internet are called hosts. Computers that route data, or data packets, to other computers are called routers. Networks and computers that are part of the global Internet possess unique registered addresses and obtain access from Internet service providers.
There are four ways to connect to the public Internet: by host, network, terminal, or gateway access. Host access is usually done either with local area networks or with the use of telephone lines and modems combined with Internet software on a personal computer. Host access allows the attached computer to fully interact with any other attached computer-limited only by the bandwidth of the connection and the capability of the computer.
Network access is similar to host access, but it is usually done via a leased telephone line that connects to a local or wide area network. All the attached computers can become Internet hosts.
Terminal access is usually done via telephone lines and modems combined with terminal-emulation software on a personal computer. It allows interaction with another computer that is an Internet host.
Gateway access is similar to terminal access but is provided via on-line or similar proprietary services, or other networks such as Bitnet, Fidonets, or UUCP nets that allow users minimally to exchange e-mail with the Internet.
The Internet technology was developed principally by American computer scientist Vinton Cerf in 1973 as part of a United States Department of Defense Advanced Research Projects Agency (DARPA) project managed by American engineer Robert Kahn. In 1984 the development of the technology and the running of the network were turned over to the private sector and to government research and scientific agencies for further development.
Since its inception, the Internet has continued to grow rapidly. In early 1995, access was available in 180 countries and there were more than 30 million users. It is expected that 100 million computers will be connected via the public Internet by 2000, and even more via enterprise internets. The technology and the Internet have supported global collaboration among people and organizations, information sharing, network innovations, and rapid business transactions. The development of the World Wide Web is fueling the introduction of new business tools and uses that may lead to billions of dollars worth of business transactions on the Internet in the future.
In the Internet nowadays, the majority of computers are from the commercial sphere (Vrabec
1996). In fact, the commercialisation of the network, which has been taking place during the last
three or four years, has caused the recent boom of the network, of the WWW service in particular
(Vrabec 1996). It all started in the network's homeland in 1986, when ARPANET was gradually
replaced by a newer and technologically better built network called NSFNET. This network was
more open to private and commercial organisations (Vrabec 1996) which, realising the potential of
the possible commercial use of the Internet, started to connect themselves to the network.
There are several possibilities how commercial organisations can benefit from their connection to
the English-speaking Internet. Internet users are supposed to be able to speak and understand
English, and actually most of them do. With the rapidly rising number of users, the network is a
potential world market (Vrabec 1996) and English will be its important tool. The status of English
as a world language, or rather its large number of people who are able to process and use
information in English, already enables commercial organisations to present themselves, their work
and their products on the Internet. Thanks to English and the Internet companies can correspond
with their partners abroad, respond to any question or give advice on any problem that their
international customers can have with their products almost immediately (Vrabec 1996).
Considering the fact that many of the biggest, economically strongest and influential organisations
are from the USA or other native English speaking countries, the commercialisation has very much reinforced the use of English on the Internet.
Cepek, Ales and Vrabec, Vladimir 1995 Internet :-) CZ, Praha, Grada
Demel, Jiri 1995 Internet pro zacatecniky, Praha, NEKLAN
Falk, Bennett 1994 InternetROADMAP, translated by David Krásenský, Praha, Computer
Jenkins, Simon 1995 "The Triumph Of English" The Times, May 1995
Philipson, Robert 1992 Linguistic imperialism, Oxford, Oxford University Press
Schmidt, Jan 1996 "Carka , hacek a WWW" Computer Echo Vol. 3/6
(also available on http://omicron.felk.cvut.cz/~comecho/ce/journal.html)
Sterling, Bruce 1993 "A short history of the Internet" The magazine Of Fantasy And Science
Fiction, Feb. 1993
Vrabec, Vladimir 1996 "Komerce na Internetu" LanCom, Vol. 4/3
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