INTRODUCTION TO DATA AND TELECOMMUNICATIONS | |||||||||||||||||
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NIC: network interface cardNOS: network operating systemTCP/IP: transmission control program/internet programNCP: network control programISO: International standards organizationOSI: open system internectionFTP: file transfer protocolFDDI: fiber distrubited data interfaceBSC: binary synchronous communicationMAU: multistation access unitTOP: technical and office protocol | ||||||||||||||||
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Brief Review of the Past, Present and Future of Telecommunication Like the history of many technologies, the history of telecommunication is like a spiral, which keeps on coming back when it moves up. It all started with the invention of telegraph in 1840 by Samuel Morse. This idea of communicating with electronic devices was further developed by two geniuses, almost simultaneously. One is Alexander Graham Bell who invented telephone in 1876. The telephone remains the most popular communication method being used up to date. The telephone circuit, on the other hand, is the best set up wired network system that has ever existed on earth. The other genius is Guglielmo Marconi, who invented the wireless telegraph in 1890. The usage of air transmittable wave to carry signal is a breakthrough in the broadcast communication. During the years that followed, both techniques have been improved dramatically to feed different needs. The introduction of computer into communication network revolutionized the whole industry. As the wired and wireless technique combines, the concept of 'distance' will be annulled in the near future. Wired Telecommunication The wired telecommunication in the United States is a monopoly. The company that control the market is American Telephone & Telegraphy (AT&T). The major benefit from this monopoly environment is that everything is standardized, such that callers can go anywhere in the state and make phone call in the same way. Although government deregulated the domination in 1984, the companies that enter the market later on, such as MCI, US sprint, also followed same standards. The introduction of computer into communication industry benefited everyone, but also created many new challenges. First of all, computer can only recognize digital data. All the analog data have to be digitized. The amount of data multiplexes by doing so. A much faster signal transmission speed is needed in order to handle this large amount of data. As the number of the computer users grows, the traditional twisted pair and coaxial cable can not handle this large amount of data any more. The users using these lines waste lots of time trying to down load data and transfer files. This problem can be solved by changing the conducted media into fiber-optic cable. The optic fibers are thin fibers the size of human hair that are made of glass or plastic. Light can transmit inside the fiber with little or no resistance. In this case, light of different wavelength can carry the signal from one end of the cable to the other. Fiber optic cable not only increases data transmission speed, but also lower the noise and provides security. Due to the multiple advantages of optic fiber over the traditional cable, the nation's second-largest cable TV company, TCI, had launched a multi-million dollar project to upgrade its network. Last month, while this project is only one third complete, AT&T, the nation's largest long-distance telephone company has announced plans to buy TCI for $48 billion dollars. This merger, could push the telecommunication business in U.S. to a new stage. With TCI's widespread cable network, especially its fiber-optic and coaxial cables, AT&T will be able to provide customers with super fast internet access and a much larger amount of TV channels, plus local and long-distance telephone service-all on one wire. AT&T Consumer Services will provide the broadest set of consumer communications services - including local, long distance, wireless and international communications, cable television, dial-up and high-speed Internet access services - all under the AT&T brand name. As Mr. C. Michael Armstrong, chairman and CEO of AT&T said in the public announcement." Today we are beginning to answer a big part of the question about how we will provide local service to U.S. consumers. We are merging with TCI not only for what it is but for what we can become together," he explained. "Through its own systems and in partnership with affiliates, AT&T Consumer Services will bring to people's homes the first fully integrated package of communications, electronic commerce and video entertainment services. And it will do it with the quality and reliability that people have come to expect from AT&T." According to AT&T, consumer services will own and operate the nation's most extensive, broadband local network platform after the merger. The new unit intends to significantly accelerate the upgrading of its cable infrastructure, enabling it to begin providing digital telephony and data services to consumers by the end of 1999, in addition to digital video services. (http://www.att.com/press/0698/980624.cha.html) The merged company, AT&T-TCI is not only more competitive in the telecommunication market, but it also is a new prototype of telecommunication company. Wireless Telecommunication Another different type of communication technique that has been developed through out the years is wireless telecommunication. Unlike communication through cables, which use electronic waves or light waves to carry the signal, the wireless telecommunication make use of waves with different frequencies. This technology was first invented in 1890 by Guglielmo Marconi. Guglielmo Marconi was born in Bologna on April 25th, 1874. As many other geniuses, he taught himself physics and electronics. Although the only schools he went to is Istituto Cavallero in Florence while he was seven years old, he found himself well ware of the ideas and theories of Maxwell, the experiments of Hertz, Righi. Calzecchi-Onesti, Branly. From school, he acquired strict, scientific way of thinking. The idea of communication using Hertzian waves came up to him during the summer of 1894, while his family was vacationing in the mountains near Biella (in the surroundings of Turin). During the following Fall, in the villa in Pontecchio near Bologna, the twenty-years-old boy transformed the granary into his laboratory, working night and day among rolls of copper wire, brass spheres, Ruhmkorff coils, Morse keys and electric bells, trying out his new ideas. The first radio sets was assembled here. The weak signals could reach few hundred meters from the window of the granary where the transmitter was placed to the hill at the end of the garden where the receiver was. On receiving the signal, the farmer waved his handkerchief to show the successful reception. But Marconi wanted much more. He wanted to get over the obstacles of the ground and connect two reciprocally invisible points. He took the receiver to the other side of the hill, where Mignani with his gun waited for the ring to sound three times. From the granary Marconi pushed three times the key of the transmitter and heard the answer of a distant gunshot: electromagnetic waves had overtaken the obstacle, radio communications where now possible! It was the month of April 1895. For this experiments Marconi used the oscillators of Hertz and Righi, but the waves where too weak to go too far. He overcame the difficulties by connecting to the oscillator an antenna and a ground, thus obtaining more power. (http://www.alpcom.it/hamradio/radeng.html) After the invention of radio by Marconi, the broadcast industry emerged. First AM, FM and short wave radio, then TV. Now every city in U. S. has its own radio and TV station. The cellular telephone was introduced in 1984. The wireless communication usually used in military in now personalized. It greatly helped in developing business. Although wireless telecommunication system might be a little slow, it can provide communication in a moving object such as a car. It can also provide communication in remote areas. Thus many companies have launched projects to develop microwave transmission using satellite. The Iridium system is one of the best developed by Motorola. It consists of 66 low earth orbit (LEO) satellite wrapping around the earth. The advantage of LEO over MEO (medium earth orbital) is that it takes signal much shorter time to travel to and from the satellite. The drawback is that it needs much higher number of satellites to cover the earth. The advantage of wireless telecommunication using satellite lured many big companies into the business. However, it still has many technique obstacles to overcome. Major one is the high cost to launch and maintain the satellite. The newest method is with HALE (high altitude long endurance) platform. It is a platform that is around 20 miles away from the earth. It hovers over cities and receiving and beaming data-rich signals to the ground. Another obstacle is the finite radio spectrum. Data compressing technology has been used to deal with this problem. The Future of Telecommunication With these new development, the cost of wireless communication will be lowered to customer affordable range. The result is a communication system based on satellite/HALE mixed with optic-fiber and terrestrial wireless networks. People in the future will be able to enjoy global high-data rate, mobile communication with a hand-set that can fit in your palm. There are two gods in fairy tales from China, the one that can see beyond and the one that can hear beyond. These two gods are responsible for getting information for the emperor in heaven. In the near future, everyone in the world will have the power of these two gods with the aid of modern techniques. | ||||||||||||||||
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