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Telecommunications Telecommunications is the transmission of various types of technologies through , , or other systems. It has its origin in the desire of humans for more than a distance greater than what is feasible with it, but with a similar scale of convenience; therefore, slow systems (such as) are excluded from the field. Telecommunications Telecommunications has evolved through numerous stages of technology, from and other visual signals (such as , , , and optic ), to and , including . Such transmission routes are often divided into , which offer the advantages of multiple concurrents. Telecommunications are often used in its plural form, because it involves many different technologies. Other examples of pre-modern long-distance communication included audio messages, such as encoded, lung blocks, and high-level technologies of the twentieth and twenty-first century for long-distance communication generally involve electrical and electromagnetic technologies, such as , , , , , , , , , and . A revolution began in the first decade of those with the pioneering developments in , which won in 1909, and other notable pioneer inventors and developers in the field of electric and electronic telecommunications. These included and (inventors of the telegraph), and (some of the inventors and developers of the phone, see ), and (inventors of the radio), as well as , and (some of the inventors of the television). According to Article 1.3 of the (RR), telecommunications is defined as "any , or receiving signals, signals, writings, images and sounds or intelligence of any nature by , , optical systems or other systems." This definition is identical to that contained in the annex to the annex (Geneva, 1992). ContentsEthology[] The word telecommunication is a compound of the Greek prefix tele (τ trackλε), which means distant, far or far, and the Latin communicator, which means to share. Its modern use is adapted to the French, because its written use was recorded in 1904 by the French engineer and novelist. The communication was first used as an English word at the end of the 14th century. It comes from the old French communication (14c., modern French communication), from the Latin communication communication communication (nominative communicatio), substantive of action of the past log participio of the communication "to share, divide; communicate, impart, inform; join, participate", literally "to make common", of the communications". History[]The beacons and pigeons have been occasionally used throughout history by different cultures. He had roots, and was later used by the Romans to help his military. he said he used pigeons as messengers in his conquest. They also transmitted the names of the victors in the different cities using homing pigeons. In the early 19th century, the government used the system in and . And in 1849, began a dove service to fly the stock prices between and , a service that operated for a year until the gap in the telegraph link was closed. In the Middle Ages, common chains were used on the hills as a means of transmitting a signal. Beacon's chains suffered the inconvenience that only a little information could happen, so the meaning of the message as "the enemy has been seen" had to be agreed in advance. A notable example of its use was during the , when a beacon chain relayed a signal from London. In 1792, a French engineer built the first fixed visual system (or ) between Paris. However, the traffic light suffered the need for qualified operators and costly towers at intervals of ten to thirty kilometers (from six to nineteen miles). As a result of the electric telegraph competition, the last commercial line was abandoned in 1880. Telegraph and telephone[]On July 25, 1837, the first commercial was shown by English, and English. Both inventors saw your device as "an improvement for the [existing] electromagnetic telegram not as a new device. He independently developed a version of the electric telegraph that unsuccessfully demonstrated on September 2, 1837. It was an important advance on the Wheatstone signaling method. The first was successfully completed on 27 July 1866, allowing for the first time transatlantic telecommunications. The conventional phone was patented in 1876. He also presented a warning to her in 1876. Gray left his caveat and because he did not object to Bell's priority, the examiner approved Bell's patent on March 3, 1876. Gray had presented her caveat for the variable resistance phone, but Bell was the first to write the idea and the first to test it on a phone.[88] invented a device that allowed the electric transmission of voice in a line almost thirty years earlier in 1849, but his device was of little practical value because it depended on the users required to place the receiver in their mouths to "hear". The first commercial telephone services were established by the Bell Phone Company in 1878 and 1879 on both sides of the Atlantic in the cities and London. Radio and television[]Starting in 1894, the Italian inventor began to develop a wireless communication using the newly discovered phenomenon of , showing for 1901 that they could be transmitted through the Atlantic Ocean. This was the beginning of . The voice and music were shown in 1900 and 1906, but they had little success early. [] The communication was first investigated by the physicist during 1894-1896, when it reached a maximum of 60 in his experiments. He also introduced the use of radio wave detection unions, when he radioed in 1901. accelerated the development of the radio for . After the war, the commercial radio began in the 1920s and became an important mass media for entertainment and news. The development of radio for the purposes of the war of aircraft and land communication, radio navigation and radar was once again accelerated. The development of radio stereo has taken place since the 1930s in the United States and the AM shifted as a dominant trade norm for the 1960s and 1970s in the United Kingdom. On March 25, 1925, he was able to demonstrate the transmission of mobile images at the London Department Store. Baird's device depended on it and thus became known as the . It formed the basis of the experimental transmissions carried out in early September 30, 1929. However, for most televisions of the twentieth century depended on what was invented by . The first version of such television to show promise was produced by his family on September 7, 1927. After , the experiments on television that had been interrupted resumed, and also became an important means of transmitting entertainment at home. Thermoonic valves[] The type of device known as thermonica valve uses the phenomenon of electrons of a heated and is used for several fundamental electronic functions such as signal and current. Non-thermal types, like a vacuum, however, achieve electron emission through the , and are used for detection of light levels. In both types, electrons accelerate from the cathode to the tube. The simplest vacuum tube, invented in 1904 by , contains only one electron heater tube and a unnode. Electrons can only flow in one direction through the device, from the cathode to the anode. Adding one or more inside the tube allows the current between the cathode and the anode to be controlled by the voltage in the grid or grids. These devices became a key component of electronic circuits for the first half of the 20th century. They were crucial to the development of radio, television, radar, long-distance and analogue and early digital networks. Although some applications had used previous technologies such as radio or computing, it was the invention of the thermonic vacuum tube that made these technologies widespread and practical, and created the discipline of . In the 1940s, the invention actually produced devices, which are smaller, more efficient, reliable and durable, and cheaper than the thermal tubes. In the mid-1960s, thermogenic tubes were replaced by the . Thermal tubes still have some applications for certain high-frequency amplifiers. It was semiconductor []The modern period of telecommunications history since 1950 is called the era, due to the wide adoption of telecommunications technology. The development of technology and significant advances in telecommunications technology, and led to a transition from state to private technologies. (MOS) as (LSI) and ( ), along with (like ), led to a transition from analog to , with the introduction of (like and ) and (like and ), lead to a rapid growth of those towards the end of the twentieth century. Transistors[] The development of technology has been critical to modern telecommunications. The first transistor, a, was invented by and in 1947. The transistor (metal-oxide-silicon field effect), also known as the MOS transistor, was later invented by and in Bell Labs in 1959. The MOSFET is the building block or "worker" of the and the , and the device most widely manufactured in history. technology, including and , drives modern telecommunications. Along with computers, other essential elements of modern telecommunications that are built from MOSFETs include , , modules, , , , , , , , and . According to the one who's been doubling every 18 months. Advances in MOS technology, including (increase at an exponential rate, as predicted by ), have been the most important factor in the rapid increase in bandwidth in telecommunications networks. Computer networks and the Internet[]On September 11, 1940, they transmitted problems for their complex numbers calculator in New York using a , and received the computed results back in . This configuration of a centralized computer () with remote control remained very popular in the 1970s. However, already in the 1960s, researchers began to investigate, a technology that sends a message in parts to their destination without passing it through a centralized. On December 5, 1969 four emerged, which constituted the beginning of the , which by 1981 had grown to 213 nodes. ARPANET eventually merged with other networks to form the . While the development of the Internet was a focus of the (IETF) that published a series of documents, there were other advances in networking, such as the developments (LAN) (1983) and (1984)[]. Wireless telecommunication[]The beginning in the nineties, with the advent of digital that leads to a social revolution, and a paradigm shift of wiring to technology, including the proliferation of commercial wireless technologies such as , , , wireless , and wireless connections. The wireless revolution has been driven by advances in (RF) and , and the transition of analog RF technology. Advances in technology (MOSFET, or MOS transistor), the key component of RF technology that allows digital wireless networks, has been central to this revolution, including MOS devices such as , , and . Digital Media[] Practical and was made possible by advances in , due to memory, storage and bandwidth requirements impractically high of non-compressed media. The most important compression technique is (DCT), an algorithm that was first proposed as a technique in 1972. On October 29, 2001, the first broadcast by Bernard Pauchon, Alain Lorentz, Raymond Melwig and Philippe Binant. Growth in transmission capacity[ The effective ability to exchange information worldwide through bidirectional telecommunications networks grew from 281 (pB) of information optimally compressed in 1986 to 471 pB in 1993, to 2.2 eB in 2000, and to 65 eB in 2007. This is the informative equivalent of two pages per person per day in 1986, and six newspapers per person per day in 2007. Given this growth, telecommunications play an increasingly important role in the global economy and the global telecommunications industry was around a sector of 4.7 billion in 2012. The services income of the world telecommunications industry was estimated at $1.5 billion in 2010, corresponding to 2.4 per cent of the world (GDP). Technical concepts[]Modern telecommunication is based on a number of key concepts that experienced progressive development and refinement in a period of much more than a century. Basic elements[] Telecommunications technologies can be divided mainly into wireless and wiring methods. In general, a basic consists of three main parts that are always present in some form or another: For example, in a large emitter is the transmitter; and the emission is the interface between the power amplifier and the "free space channel". The free space channel is the medium of transmission; and the antenna of the receiver is the interface between the free space channel and the receiver. Next, the target of the radio signal, and here is where it turns from electricity to sound so people listen. Sometimes telecommunications systems are (two-way systems) with a single work box such as the transmitter and a receiver, or a transmitter. For example, one is a transceiver. The transmission electronics and the receiver electronics within a transceiver are actually quite independent of each other. This can be easily explained by the fact that radio transmitters contain power amplifiers that operate with measured or edible power, but radio receivers take care of the radio powers that are measured in or . Therefore, the transmitters have to be carefully designed and built to isolate their high-power circuits and their low-power circuits one from the other, as well as not to cause interference. Telecommunications on fixed lines is called because it is between a transmitter and a receiver. Telecommunications through broadcasting is called because it is between a powerful transmitter and numerous low-powered but sensitive radio receivers. Telecommunications in which multiple transmitters and multiple receptors have been designed to cooperate and share the same physical channel are called . The exchange of physical channels through multiplexing usually gives great cost reductions. Multiplexed systems are set in telecommunications networks, and multiplex signals are changed to nodes through the right target terminal receiver. Analog versus digital communications[ ] Communication signals can be sent by or . There are systems and systems. For an analog signal, the signal is continuously varied with respect to information. In a digital signal, the information is encoded as a set of discrete values (e.g., a set of about zeros). During propagation and reception, the information contained in analog signals will inevitably be degraded by . (The output of a transmitter is free of noise for all practical purposes.) Commonly, noise in a communication system can be expressed as an addition or subtraction of the desirable signal in a completely. This noise form is called, with the understanding that noise can be negative or positive in different moments of time. The noise that is not additive noise is a much more difficult situation to describe or analyze, and these other types of noise will be omitted here. On the other hand, unless the added disturbance of noise exceeds a certain threshold, the information contained in the digital signals will remain intact. Its noise resistance represents a key advantage of digital signals over analog signals. Communication channels[] The term "channel" has two different meanings. In one sense, a channel is the physical environment that carries a signal between the transmitter and the receiver. Examples of this include for sound communications, glass for some types of , for communications through voltages and electric currents in them, and for communications with , , , and . Coaxial cable types are classified by type RG or "radio guide", terminology derived from World War II. The various RG denominations are used to classify specific signal transmission applications. This last channel is called the "free space channel". The sending of radio waves from one place to another has nothing to do with the presence or absence of an environment between the two. Radio waves travel through a perfect as easily as they travel through the air, fog, clouds or any other type of gas. The other meaning of the term "channel" in telecommunications is seen in the phrase, which is a subdivision of a means of transmission so that it can be used to send multiple information flows simultaneously. For example, a radio station can transmit free-space radio waves in frequencies in the 94.5 (megahertz) neighborhood, while another radio station can simultaneously transmit radio waves to frequencies in the 96.1 MHz neighborhood. Each radio station would transmit radio waves on a frequency of about 180 (kilohertz), centered on frequencies like the previous one, which are called the . Each station of this example is separated from its adjacent stations by 200 kHz, and the difference between 200 kHz and 180 kHz (20 kHz) is an engineering benefit for imperfections in the communication system. In the previous example, the "free space channel" has been divided into communication channels according to , and each channel assigns a separate frequency bandwidth in which to emit radio waves. This system of dividing the medium into channels as often called ". Another term for the same concept is "", which is most commonly used in optical communications when multiple transmitters share the same physical medium. Another way of dividing a medium of communication into channels is to assign each sender a recurring time segment (a "time scroll", for example, 20 of each second), and allow each sender to send messages only within their own time slot. This method of dividing the medium into communication channels is called "" (TDM), and is used in optical fiber communication. Some radio communication systems use TDM within an assigned FDM channel. Therefore, these systems use a TDM and FDM hybrid. TDMModulation[] The configuration of a signal to transmit information is known as . Modulation can be used to represent a digital message as an analog wave form. This is commonly called—a term derived from the oldest use of the Morse Code in telecommunications—and there are several key techniques (these include, , and ). The system ", for example, uses the phase scroll key system to exchange information between various devices. In addition, there are combinations of phase lock and amplitude key and speed change that is called (in the field jargon) " (QAM) that are used in high capacity digital radio communication systems. Modulation can also be used to transmit low frequency analog signal information to higher frequencies. This is useful because low-frequency analog signals cannot be effectively transmitted over free space. Therefore, the information of a low-frequency analog signal should be impressed on a higher frequency signal (known as the "") before transmission. There are several different modulation schemes available to achieve this [two of the most basic being (AM) and (FM)]. An example of this process is the voice of a jockey disc that is impressed on a 96 MHz carrier wave with frequency modulation (the voice would be received on a radio like the "96 FM" channel). In addition, modulation has the advantage that you can use the multiplexing frequency division (FDM). Telecommunications Networks[]A is a collection of transmitters, receivers and send messages to each other. Some digital communications networks contain one or more that works together to transmit information to the correct user. An analog communications network consists of one or more that establishes a connection between two or more users. For both types of network, it may be necessary to amplify or recreate the signal when transmitted over long distances. This is to fight that you can make the indistinguishable signal of noise. Another advantage of analog digital systems is that their output is easier to store in memory, i.e. two states of tension (high and low) are easier to store than a continuous range of states. Social impact[]Telecommunications has a significant social, cultural and economic impact on modern society. In 2008, the estimates placed the revenues of the 's at $4.7 billion or just under 3 per cent of the (official exchange rate). Several sections below examine the impact of telecommunications on society. Microeconomics[] On the scale, companies have used telecommunications to help build global business empires. This is evident in the case of the online retailer but, according to academic Edward Lenert, even the conventional retailer has benefited from a better telecommunications infrastructure compared to its competitors. In cities around the world, homeowners use their phones to order and organize a variety of home services ranging from pizza deliveries to electricians. It has been noted that even relatively poor communities use telecommunications to take advantage of them. In 's, isolated villagers use cell phones to speak directly to wholesalers and organize a better price for their goods. In , coffee producers share mobile phones to follow time variations in coffee prices and sell at the best price. Macroeconomics[] On the macroeconomic scale, Lars-Hendrik Röller suggested a causal link between good telecommunications infrastructure and economic growth. Few dispute the existence of a correlation, although some argue that it is incorrect to see the relationship as causal. Owing to the economic benefits of good telecommunications infrastructure, there is growing concern about the unwavering access to telecommunications services among several countries around the world, this is known as the . A 2003 study by ITU revealed that approximately one third of countries have less than one mobile subscription for every 20 people and one third of countries have less than one landline subscription for every 20 people. With regard to Internet access, approximately half of all countries have less than one in 20 people with Internet access. From this information, as well as educational data, ITU was able to compile an index that measures the general capacity of citizens to access and use information and communication technologies. Through this measure, Sweden, Denmark and the highest rank, while African countries Nigeria, Burkina Faso and Mali received the lowest. Social impact[] Telecommunication has played an important role in social relations. However, devices such as the phone system were originally announced with an emphasis on the practical dimensions of the device (such as the ability to perform business or order home services) rather than the social dimensions. It was not until the end of the 20s and 1930s that the social dimensions of the device became a prominent theme in phone ads. The new promotions began to appeal to the emotions of consumers, highlighting the importance of social conversations and staying connected with family and friends. Since then, the role of telecommunications in social relations has become increasingly important. In recent years, popularity has increased dramatically. These sites allow users to communicate with each other, as well as publish photographs, events and profiles for others to see. Profiles may list a person's age, interests, sexual preference and relationship status. In this way, these sites can play an important role in everything, from organizing social commitments to . Prior to social networks, technologies such as (SMS) and the phone also had a significant impact on social interactions. In 2000, the market research group reported that 81 per cent of SMS users aged 15-24 in the United Kingdom had used the service to coordinate social arrangements and 42 per cent to flirt. Entertainment, news and advertising[] Preferences from the American news source in 2006. Local television 59% National television 47% Radio 44% Local document 38% Internet 23% National document 12% Survey allowed multiple responses In cultural terms, telecommunications have increased the capacity of the public to access music and cinema. With television, people can watch movies that have not seen before in their own home without having to travel to the video store or to the cinema. With radio and Internet, people can listen to music they haven't heard before without having to travel to the music store. Telecommunications have also transformed the way people get their news. A 2006 (right) survey of a little more than 3,000 Americans by the Pew Internet and Non-profit American Life Project in the United States, most of them specified television or radio on newspapers. Telecommunications have had an equally significant impact on advertising. He reported that in 2007, 58 per cent of publicity expenditures in the United States were spent on telecommunications-dependent media. Advertising agencies in the United States in 2007 Mediana Expenditure Internet 7.6% $11.31 million Radio 7.2% $10.69 million Cable TV 12.1% $18.0 million Television 2.8% $4.17 million Spot TV 11.3% 16.82 million dollars Red TV 17.1% $25,450 million Newspaper 18.9% $28,222 million Magazine 20.4% $30.33 million Outdoor 2.7% $4.02 million Total 100% $149 million Regulation[] Many countries have enacted laws that conform to the International Telecommunication Regulations established by the International Telecommunication Union (ITU), which is the "leading UN organization for information and communications technology issues." In 1947, at the Atlantic City Conference, ITU decided to "secur international protection to all frequencies registered in a new list of international frequencies and used in accordance with the Radio Regulations." According to the ITU Radio Regulations adopted in Atlantic City, all frequencies mentioned in the International Frequency Registration Board, reviewed by the board of directors and registered in the International Frequency List "will have the right to international protection against harmful interferences." Globally, political discussions and laws on telecommunications management and transmission have been held. Discussions discuss some discussions on the balance of conventional communication, such as printing and telecommunications, such as broadcasting. The beginning of the first explosion of international broadcasting propaganda. Countries, their Governments, insurgents, terrorists and militias have used telecommunications and broadcasting techniques to promote. Patriarchal propaganda for political movements and colonization began in the mid-30s. In 1936, the BBC transmitted propaganda to the Arab world to offset in part similar emissions from Italy, which also had colonial interests in North Africa. Modern insurgents, like the most recent, often use intimidating phone calls, SMS and the distribution of sophisticated videos of an attack on coalition troops within the hours of the operation. "The Sunni insurgents even have their own television station, which, although prohibited by the Iraqi government, still broadcast from Iraqi Kurdistan, even as the coalition's pressure has forced them to change satellite several times." On 10 November 2014, it recommended reclassification as a maintenance service. Modern media[] Equipment sales from around the world[] According to data collected by Gartner and Ars Technica sales of the main consumer telecommunications equipment worldwide in millions of units was: Equipment/year 1975 1980 1985 1990 1994 1996 1998 2000 2002 2004 2006 2008 Computers 0 1 8 20 40 75 100 135 130 175 230 280 Cellulars N/A N/A N/A N/A N/A N/A 180 400 420 660 830 1000 Telephone[] In a network, the caller is connected to the person they want to speak to by switches on several. The switches form an electrical connection between the two users and the configuration of these switches is electronically determined when the call number. Once the connection is made, the caller's voice becomes an electric signal using a small in the caller. This electrical signal is sent through the network to the user at the other end where it is converted back into sound by a small on that person's phone. Since 2015, the fixed phones in most residential homes are analogous, i.e. the voice of the speaker directly determines the voltage of the signal. Although short distance calls can be handled from the end to the end as analog signals, more and more telephone service providers are turning signals into digital signals for transmission. The advantage of this is that digitalized voice data can travel side by side with Internet data and can be perfectly reproduced in long-distance communication (as opposed to analog signals that are inevitably impacted by noise). Mobile phones have had a significant impact on phone networks. Mobile phone subscriptions now exceed fixed-line subscriptions in many markets. Mobile phone sales in 2005 amounted to 816.6 million people, with an almost equal figure between the Asian and Pacific markets (204 m), Western Europe (164 m), CEMEA (Central Europe, the Middle East and Africa) (153.5 m), North America (148 m) and Latin America (102 m). In terms of new subscriptions over the five years of 1999, Africa has surpassed other markets with a growth of 58.2 per cent. More and more these phones are being treated by systems where voice content is transmitted digitally, as or with many markets that choose to depredict analogous systems like . There have also been dramatic changes in the telephone communication behind the scenes. Since the 1988 operation, the 1990s saw the widespread adoption of optical fibre-based systems. The benefit of communicating with optical fibers is that they offer a drastic increase in data capacity. TAT-8 itself was able to carry 10 times more phone calls than the last copper cable placed at that time and today's fiber optic cables can carry 25 times more phone calls like TAT-8. This increase in data capacity is due to several factors: First, optical fibers are physically much smaller than competing technologies. Second, they do not suffer from what it means that several hundred of them can easily be grouped into a single cable. Finally, improvements in multiplexing have resulted in exponential growth in single-fibre data capacity. Helping communication on many modern fiber optic networks is a protocol known as (ATM). The ATM protocol allows the side to side mentioned in the second paragraph. It is suitable for public telephone networks because it establishes a pathway for data through the network and associates with the way. The traffic contract is essentially an agreement between the customer and the network on how the network is to handle the data; if the network cannot meet the terms of the traffic contract it does not accept the connection. This is important because phone calls can negotiate a contract to ensure a constant bit rate, which will ensure that a caller's voice is not delayed in parts or cut completely. There are ATM competitors, such as (MPLS), who perform a similar task and are expected to replace ATM in the future. Radio and television[] In a radio broadcasting system, the high power center transmits a high frequency to numerous low-power receptors. The high frequency wave sent by the tower is modulated with a signal containing visual or audio information. The receiver is then to collect the high frequency wave and is used to recover the signal that contains visual or audio information. The transmission signal can be analogous (the signaling is continuously varied with respect to information) or digital (the information is encoded as a set of discrete values). He is a critical turning point in its development, with many countries moving from analog to digital emissions. This movement is possible by the production of cheaper, faster and more capable. The main advantage of digital transmissions is that they prevent several complaints common to traditional analogue transmissions. For television, this includes removing problems like, and another distortion. These occur due to the nature of analogue transmission, which means that noise disturbances will be evident in the final output. Digital transmission overcomes this problem because digital signals are reduced to discrete values at the reception and therefore small disturbances do not affect the final output. In a simplified example, if a 1011 binary message was transmitted with signal amplitudes [1.0 0.0 1.0] and received with signal amplitudes [0.9 0.2 1.1 0.9], it would still be decoded with binary message 1011 — a perfect reproduction of what was sent. From this example, a problem with digital transmissions can also be seen that if the noise is large enough can significantly alter the decoded message. Using a receiver can correct a handful of bit errors in the resulting message, but too much noise will lead to incomprehensible output and therefore a breakdown of transmission. In digital television broadcasting, there are three rules that are likely to be adopted worldwide. These are the , and the standards; the adoption of these standards so far is presented on the map captured. The three standards use for video compression. ATSC uses for audio compression, ISDB uses (MPEG-2 Part 7) and DVB does not have any standard for audio compression, but usually uses . The choice of modulation also varies between the schemes. In digital audio broadcasting, standards are much more unified with virtually all countries that opt to adopt the norm (also known as the norm). The exception is the United States that has chosen to adopt . HD Radio, unlike Eureka 147, is based on a transmission method known as transmission that allows digital information "piggyback" on normal analogue AM or FM transmissions. However, despite the outstanding change to digital television, most countries continue to broadcast analogously. One exception is the United States that completed the analogue transmission of television (for all television stations but very low power) on 12 June 2009 after delaying the switching time twice. Kenya also completed the analogue television broadcast in December 2014 after multiple delays. For analog television, there were three standards in use for broadcasting color television (see an adoption map). These are known as (German designed), (American designed), and (French designed). For analogue radio, the change to digital radio becomes more difficult for the higher cost of digital receivers. The choice of modulation for analogue radio is typically between amplitude (AM) or frequency modulation (FM). To achieve , a modulated range sub-worker is used for , and square amplitude modulation is used for stereo AM or . AMFMInternet[] It is a global network of computers and computer networks that communicate with each other using the (IP). Any computer on the Internet has a unique one that can be used by other computers for the information route to it. Therefore, any computer on the Internet can send a message to any other computer using your IP address. These messages carry with them the original IP address of the computer allowing the bidirectional communication. Therefore, the Internet is an exchange of messages between computers. It is estimated that 51% of the information that was transported through bidirectional telecommunications networks in the year 2000 flowed over the Internet (most of the remainder (42%) through the ). By 2007 the Internet clearly dominated and captured 97 per cent of all information on telecommunications networks (most of the rest (2%) a). Since 2008, it is estimated that 21.9 per cent of the world ' s population has Internet access with the highest rates of access (measured as a percentage of the population) in North America (73.6 per cent), Oceania/Australia (59.5 per cent) and Europe (48.1 per cent). In terms of , Iceland (26.7%), South Korea (25.4%) and Holland (25.3%) led the world. The Internet works partly because they govern how computers and routers communicate with each other. The nature of computer network communication is given to a layer approach where individual protocols in the protocol stack work more or less regardless of other protocols. This allows lower-level protocols to be customized for the network situation, without changing the way the higher-level protocols work. A practical example of why this is important is because it allows you to run the same code regardless of whether the computer on which it runs is connected to the Internet via an Ethernet or connection. Protocols are often spoken in terms of their place in the OSI reference model (photo on the right), which emerged in 1983 as the first step in an unsuccessful attempt to build a universally adopted network protocol suite. For the Internet, the physical environment and the data link protocol can vary several times as packages cross the globe. This is because the Internet does not place restrictions on which physical medium or data link protocol is used. This leads to the adoption of means and protocols that best adapt to the situation of the local network. In practice, greater intercontinental communication will use the Asynchronous Transfer Mode (ATM) protocol (or a modern equivalent) at the top of the optical fiber. This is due to the fact that for most intercontinental communications the Internet shares the same infrastructure as the telephone network switched by the public. In the network layer, things are standardized with the Internet Protocol (IP) adopted for . For the World Wide Web, these "IP addresses" are derived from the human legible form using the (e.g. 72.14.207.99 is derived from www.google.com). At this time, the most widely used version of the Internet Protocol is version four, but a move to version six is imminent. In the transport layer, most of the communication adopts the Transmission Control Protocol (TCP) or the (UDP). TCP is used when it is essential that each message sent be received by the other team, while the UDP is used when it is merely desirable. With TCP, packages are retransmitted if they are lost and placed in order before they are presented to higher layers. With UDP, packages are not ordered or retransmitted if lost. Both TCP and UDP packages carry with them to specify which application or package should be handled by. Because certain application level protocols use, network administrators can manipulate traffic to suit particular requirements. Examples are restricting Internet access by blocking traffic intended for a given port or to affect the performance of certain applications by assigning. Above the transport layer, there are certain protocols that are sometimes used and loosely fit into the session and presentation layers, especially protocols (SSL) and (TLS). These protocols ensure that data transferred between two parties are completely confidential. Finally, in the application layer, there are many of the protocols that Internet users would be familiar with such as (navigation monitoring), (e-mail), (file transfer), (Internet chat), (sharing files) and (constant machining). (VoIP) allows you to use data packages for voice communications. Data packets are marked as voice-type packages and may be prioritized by network administrators so that the synchronized conversation in real time is less subject to containment with other types of data traffic that can be delayed (i.e., file transfer or email) or damped in advance (i.e., audio and video) without detriment. That prioritization is good when the network has enough capacity for all the calls VoIP that are made at the same time and the network is enabled to prioritize, that is, a private corporate-style network, but the Internet is not usually managed in this way and therefore there can be a big difference in the quality of the calls VoIP through a private network and on the public Internet. Local area networks and wide area networks[]Despite the growth of the Internet, the features of computer networks (LANs) that do not extend beyond a few kilometres remain different. This is because networks on this scale do not require all the features associated with larger networks and are often more profitable and efficient without them. When they are not connected to the Internet, they also have the advantages of privacy and security. However, the lack of direct Internet connection does not provide safe protection against hackers, military forces or economic powers. These threats exist if there is any method to remotely connect to the LAN. (WANs) are private computer networks that can be extended for thousands of kilometres. Once again, some of its advantages include privacy and security. The first users of private information networks and the media include armed forces and intelligence agencies that must keep their information safe and secret. Several sets of communication protocols emerged in the mid-1980s to fill the gaps between the data link layer and the application layer of the . These included , , and with the dominant protocol established during the 1990s being IPX due to its popularity with users. existed at this time, but it was usually only used by large government and research institutions. As the Internet grew in popularity and its traffic was necessary to be routed into private networks, the TCP/IP protocols replaced existing local network technologies. Additional technologies, such as, allowed TCP/IP-based computers to be self-configured on the network. These functions also existed in AppleTalk/IPX/ NetBIOS protocol sets. While the asynchronous transfer mode (ATM) or the multiprotocol switch (MPLS) are typical data link protocols for larger networks such as WANs; Ethernet and Token Ring are typical data link protocols for LANs. These protocols differ from previous protocols in which they are simpler, for example, omit features such as guarantees, and offer. Both differences allow for more economical systems. Despite the modest popularity of Token Ring in the 1980s and 1990, virtually all LANs now use wireless or cable Ethernet facilities. In the physical layer, most cabling Ethernet implements use (including common networks). However, some early deployments used heavier coaxial cables and some recent (especially high-speed) deployments use optical fibers. When optical fibers are used, the distinction should be made between multimode fibers and monomode fibers. It can be considered as thicker optical fibers that are cheaper to make devices for, but that suffers from lower bandwidth and worse attenuation, which implies a poorer long distance performance. 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