The Basic Principles Of Networking
Technological advances in telecommunications are of increasing interest to educators. The proliferation of microcomputers and personal workstations has increased the need for sharing resources and information. The dependence upon information has accelerated, and educators are using a variety of communication devices. Information is being created, managed and exchanged by combining computing with communication techniques and facilities.
Networks are the means by which computing and telecommunications technologies are merged. Network components may consist of computers, telephones, data terminals, switches, communication channels, network protocols and operating software, all of which function together to provide for the exchange of information.
As networking and telecommunications have evolved, the national telephone network has become a telecommunications network. Telephone lines are no longer limited to the exchange of voice signals. Data of all varieties is increasingly transmitted through telephone lines. An understanding of how the telephone network is changing into a telecommunications network through the integration of voice and data services is essential to better utilize these technological tools and to plan for future growth.
To make this information available, the authors wrote a book titled Telecommunications Fundamentals for Bell Atlantic Co. The concepts found in this article are expanded in the book, copies of which may be obtained from Bell of Pennsylvania.
What Is Telecommunications?
In the early '60s, when computers first became of operational value, their use was restricted primarily to essential business and scientific applications. Input and output devices, such as terminals and printers, were located close to the computer. Limitations on the distances between computers and peripherals hindered the usefulness of early computer systems. However, utilization was soon extended beyond the boundaries of the computer room through the application of telecommunications technology.
Telecommunications can be defined as the electronic process that permits the passing of information from one sender to one or more receivers with the output in a usable form (printed copy, fixed or moving pictures, optical signals). It includes all services, products, media and methodologies used to deliver information electronically, from a simple telephone to sophisticated fiber-optic networks.
In telecommunications, a physical or logical path allowing the transmission of information is called a channel. A communication channel or electronic pathway is used to carry the signals of voice, data or video information. Channels are also called circuits, lines, access links and facilities. They are most often provided through wire cables, coaxial cable and/or high-frequency radio beams, such as those transmitted by microwave systems and satellites.
Through the use of telecommunications, machines talk to one another. Physical limitations imposed by the electronic connection between terminal devices and computers are removed. Distance is not a limitation; therefore, information can be shared quickly and easily across a campus, across a city and throughout the world.
Communication channels are referred to as switched or nonswitched. A switched channel is typically a two-wire circuit fixed at one end to a user station and connected at the other end to a communication switch. An example of a switched channel is "Plain Old Telephone Service," or POTS. The user either dials a telephone number or commands the data equipment to send a pre-recorded number to the communication switch. The numbers received by the switch are instructions which determine the desired connection. Non-switched channels are either two-wire or four-wire circuits dedicated to a predetermined set of users for voice, data, video and telemetry applications. …