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I. - , :
data communications traffic
voice and data carrier
basic route interface
primary rate interface
repeater device
terminal adapter
adapter card
II. , :
open communications network; fee basis; state-owned and operated public network; closed communication system; knowledge workers; integrated services digital network phone line; telephone company central office; phone company switch; conventional analog-to-digital connections
III. II, .
IV. II. :
Several types of private networks exist in business today, serving a variety of needs for knowledge workers.
V. "There + be" .
VI. .
VII. " II ". , to have , , , - : He has his shoes mended in that shop = .
You have your computer connected to the Internet.
VIII. .
IX. " which", .
X. , .
XI. , .
XII. , :
1. There exist special-purpose memories where writing is seldom necessary.
2. The basic job of computers is processing information.
3. A communications channel is the means of transmitting data or information between terminals.
4. Sharing data means that all the LAN users access one database and get the most up-to-date data.
5. Programming a computer involves analysing the problem to be solved and a plan to solve it.
6. By the mid-1980s, thousands of office workers began bringing their own personal computers to work in order to use the new business software written for PCs.
XIII. . .
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Public Networks
1. A public network is an open communications network available for use by anyone, usually on a fee basis. Many countries have a state-owned and operated public network for telephone, telegraph, e-mail and Internet communications. Even though originally designed for voice messages, these public networks carry a large volume of data communications traffic today.
Private Networks
2. In addition to public networks, many private networks exist. A private network is a closed communication system, usually confined to a particular company, governmental entity, or other group. Several types of private networks exist in business today, serving a variety of needs for knowledge workers. These networks, large or small, are categorized in two ways: by topology, or the physical layout of network devices and needs and by the proximity of the devices and nodes to each other.
Integrated Services Digital Networks
3. ISDN, or the Integrated Services Digital Network, is a completely digital communications network. Introduced by AT&T in the 1980s, it is gradually gaining more favour. ISDN supports multiple voice and data carriers in what are termed bearer channels (B channels). There is also a separate data channel (D channel) available.
4. There are two basic types of ISDN service. Basic Rate Interface (BRI), with two B channels and one D channel, for most home and small business uses. This means you could conduct a telephone conversation and have your computer connected to the Internet simultaneously, on the B Channel, with a single ISDN line. Primarily Rate Interface (PRI), with up to 23 B channels plus one D channel, is for larger enterprises.
5. To access BRI service, users must obtain an ISDN phone line, which usually means being within about 3.4 miles or 5.5 km of the telephone company central office. Longer distances require repeater devices. Customers will also need special equipment, such as ISDN terminal adapters or routers, or a PC adapter card, to communicate with the phone company switch as well as with other ISDN devices. ISDN calls are usually (in the U.S.) charged by the minute, even for local calls. Rates can vary from state to state. Whatever the cost, ISDN is truly digital, which means no modems are needed and connection speeds are five times faster than conventional analog-to-digital connections.
XIV. .
XV. .
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The Internet. Intranets
.
I. - , :
advanced Internet development
to conduct experiments
communications infrastructure
middleware
secure firewall
proprietary network
II. :
corporation, development, simply, researcher, environmental, affordable, organizational, employee, experimentation
III. , " " . .
IV. , :
university corporation; health care; development tools; secure confines; corporate partners
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V. .
VI. , . .
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IX. -ed, .
X. " as ", .
XI. .
XII. , :
1. Sometimes it is difficult to predict the failure or success of a computer system without testing it.
2. Computer is any of various automatic electronic devices that solve problems by processing data.
3. In solving the arithmetical problem the computer failed.
4. On creating the means for manufacturing the data the users wanted to access the data quickly.
XIII. c . .
XIV. . .
The Internet
1. What we use today is called the Internet, or Internet I. What we'll use tomorrow is being called Internet 2, and the University Corporation for Advanced Internet Development is creating it. Some of its objectives include
Demonstrate new applications that can dramatically enhance researchers' ability to collaborate and conduct experiments
Demonstrate enhanced delivery of education and other services (such as health care, environmental monitoring) by taking advantage of "virtual proximity" created by an advanced communications infrastructure
Support development and adoption of advanced applications by providing middleware and development tools
Facilitate development, deployment, and operation of an affordable communications infrastructure
Promote experimentation with the next generation of communications technologies
Encourage transfer of technology from Internet 2 to the rest of the Internet
Internet 2 is expected to be deployed around the year 2002.
Intranets
2. An intranet is simply an Internet within the secure confines of an enterprise. It provides services to users from a corporate or organizational server, and is often connected to the Internet through a secure firewall. As with the Internet, the networking infrastructure is built in. Remote employees can use the intranet in the same way they would use the Internet, except that is proprietary and secure. More and more enterprises are establishing intranets as a way of providing a wide range of computing applications and services to users and corporate partners or customers without the cost of building proprietary networks.
XV. .
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