1.
Telephone
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A telephone, or phone, is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be heard directly. In 1876, Scottish emigrant Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice and this instrument was further developed by many others. The telephone was the first device in history that people to talk directly with each other across large distances. Telephones rapidly became indispensable to businesses, government, and households, the essential elements of a telephone are a microphone to speak into and an earphone which reproduces the voice in a distant location. Until approximately the 1970s most telephones used a dial, which was superseded by the modern DTMF push-button dial. The receiver and transmitter are usually built into a handset which is held up to the ear, the dial may be located either on the handset, or on a base unit to which the handset is connected. The transmitter converts the sound waves to electrical signals which are sent through the network to the receiving phone. The receiving telephone converts the signals into audible sound in the receiver, telephones permit duplex communication, meaning they allow the people on both ends to talk simultaneously. The first telephones were connected to each other from one customers office or residence to another customers location. Being impractical beyond just a few customers, these systems were replaced by manually operated centrally located switchboards. For greater mobility, various systems were developed for transmission between mobile stations on ships and automobiles in the middle 20th century. Hand-held mobile phone]s was introduced for personal service starting in 1973, by the late 1970s several mobile telephone networks operated around the world. In 1983, the Advanced Mobile Phone System was launched, offering a standardized technology providing portability for users far beyond the residence or office. These analog cellular system evolved into digital networks with better security, greater capacity, better regional coverage, the public switched telephone network, with its hierarchical system of many switching centers, interconnects telephones around the world for communication with each other. With the standardized international numbering system, E.164, each line has an identifying telephone number. Although originally designed for voice communications, convergence has enabled most modern cell phones to have many additional capabilities. Since 1999, the trend for mobile phones is smartphones that integrate all mobile communication, a traditional landline telephone system, also known as plain old telephone service, commonly carries both control and audio signals on the same twisted pair of insulated wires, the telephone line. The control and signaling equipment consists of three components, the ringer, the hookswitch, and a dial, the ringer, or beeper, light or other device, alerts the user to incoming calls
2.
Trunking
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In telecommunications, trunking is a method for a system to provide network access to many clients by sharing a set of lines or frequencies instead of providing them individually. This is analogous to the structure of a tree with one trunk, examples of this include telephone systems and the two-way radios commonly used by police agencies. More recently port trunking has been applied in computer networking as well, a trunk is a single transmission channel between two points, each point being either the switching center or the node. In two-way radio communications, trunking refers to the ability of transmissions to be served by free channels whose availability is determined by algorithmic protocols, the cashier represents each radio channel, and each customer represents a radio user transmitting on their radio. Trunked radio systems pool all of the cashiers into one group, in a TRS, individual transmissions in any conversation may take place on several different channels. In the shopping analogy, this is as if a family of shoppers checks out all at once and are assigned different cashiers by the traffic manager, similarly, if a single shopper checks out more than once, they may be assigned a different cashier each time. Trunked radio systems provide greater efficiency at the cost of greater management overhead, the store managers orders must be conveyed to all the shoppers. This is done by assigning one or more channels as the control channel. TRSs have grown massively in their complexity since their introduction, and this is similar to the idea of a chain of grocery stores. The shopper generally goes to the nearest grocery store, but if there are complications or congestion, TRSs have greater risks to overcome than conventional radio systems in that a loss of the store manager would cause the systems traffic to no longer be managed. In this case, most of the time the TRS will automatically switch to a control channel, or in more rare circumstances. In spite of these risks, TRSs usually maintain reasonable uptime, trunk lines are used for connecting a private branch exchange to a telephone service provider. When needed they can be used by any telephone connected to the PBX, Trunking saves cost, because there are usually fewer trunk lines than extension lines, since it is unusual in most offices to have all extension lines in use for external calls at once. Trunk lines transmit voice and data in such as analog, T1, E1. The dial tone lines for outgoing calls are called DDCO trunks, in the UK and the Commonwealth countries, a trunk call was the term for long distance calling, involving more than one telephone exchange, in contrast to making a local call. Trunking also refers to the connection of switches and circuits within a telephone exchange, Trunking is closely related to the concept of grading. Trunking allows a group of switches at the same time. Thus the service provider can provide a number of circuits than might otherwise be required, allowing many users to share a smaller number of connections
3.
Switchboard operator
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Each pair of plugs was part of a cord circuit with a switch associated that let the operator participate in the call. Each jack had a light above it that lit when the receiver was lifted. Lines from the office were usually arranged along the bottom row. Switchboard operators are required to have very strong communication skills. Before the advent of automatic exchanges, an operators assistance was required for anything other than calling telephones across a party line. Callers spoke to an operator at a Central Office who then connected a cord to the circuit in order to complete the call. Being in complete control of the call, the operator was in a position to listen to private conversations, automatic, or Dial systems were developed in the 1920s to reduce labor costs as usage increased, and to ensure privacy to the customer. As phone systems became more sophisticated, less direct intervention by the operator was necessary to complete calls. As well as the people that were employed by the networks, operators were required at private branch exchanges to answer incoming telephone calls. Today, most large organizations have direct-dial extensions, smaller workplaces may have an automated system which allows callers to enter the extension of the called party, or a receptionist who answers calls and performs operator duties. Operators employed in healthcare settings have other duties, such as entry, greeting patients and visitors, taking messages, triaging. Experienced, well trained operators generally command a higher salary, in January 1878 George Willard Croy became the worlds first telephone operator when he started working for the Boston Telephone Dispatch company. Emma was hired by Alexander Graham Bell, and reportedly, could remember every number in the directory of the New England Telephone Company. Emma Nutt became the first female telephone operator on 1 September 1878 when she started working for the Boston Telephone Dispatch company, more women began to replace men within this sector of the workforce for several reasons. The companies observed that women were generally more courteous to callers, however, a contributing factor to women entering this workforce was because womens labour was cheap in comparison to mens. Specifically, women were paid from one half to one quarter of a mans salary, attendant console Operator assistance Private branch exchange Telephone operator Telephone switchboard Media related to Telephone operators at Wikimedia Commons
4.
North American Numbering Plan
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The North American Numbering Plan is a telephone numbering plan that encompasses 25 distinct regions in twenty countries primarily in North America, including the Caribbean and the U. S. territories. Not all North American countries participate in the NANP, each participating country forms a regulatory authority that has plenary control over local numbering resources. The FCC also serves as the U. S. regulator, Canadian numbering decisions are made by the Canadian Numbering Administration Consortium. The NANP divides the territories of its members into numbering plan areas which are encoded numerically with a telephone number prefix. Each telephone is assigned a telephone number unique only within its respective plan area. The telephone number consists of a central office code and a four-digit station number. The combination of a code and the telephone number serves as a destination routing address in the public switched telephone network. For international call routing, the NANP has been assigned the calling code 1 by the International Telecommunications Union. The North American Numbering Plan conforms with ITU Recommendation E.164, from its beginnings in 1876 and throughout the first part of the 20th century, the Bell System grew from essentially local or regional telephone systems. These systems expanded by growing their subscriber bases, as well as increasing their service areas by implementing additional local exchanges that were interconnected with tie trunks and it was the responsibility of each local administration to design telephone numbering plans that accommodated the local requirements and growth. As a result, the Bell System as a developed into an unorganized system of many differing local numbering systems. The diversity impeded the efficient operation and interconnection of exchanges into a system for long-distance telephone communication. The new numbering plan was accepted in October 1947, dividing most of North America into 86 Numbering Plan Areas. Each NPA was assigned a Numbering Plan Area code, often abbreviated as area code and these codes were first used by long-distance operators to establish long-distance calls between toll offices. The first customer-dialed direct call using area codes was made on November 10,1951, from Englewood, New Jersey, to Alameda, California. Direct distance dialing was introduced across the country and by the early 1960s most areas of the Bell System had been converted and it was commonplace in cities. In the following decades, the system expanded to all of the United States and its territories, Canada, Bermuda. By 1967,129 area codes had been assigned, mexican participation was planned, but implementation stopped after two area codes had been assigned and Mexico opted for an international numbering format, using country code 52
5.
Direct distance dialing
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Direct distance dialing is a telecommunication service feature in which a caller may, without operator assistance, call any other user outside the local calling area. Direct dialing by subscribers typically requires extra digits to be dialed as prefixes than for dialing within the area or within an area code. DDD also extends beyond the boundaries of national public telephone network, DDD was the term used when the North American Numbering Plan was implemented in the 1950s. In the United Kingdom and other parts of the Commonwealth of Nations, the equivalent terms are or were STD, for subscriber trunk dialing, the first direct-dialed long-distance telephone calls were possible in the New Jersey communities of Englewood and Teaneck starting on November 10,1951. Whitehorse, Yukon, had numbers from 1965, but the necessary switching equipment was not in place locally until 1972. The No.4 Crossbar switching system had been introduced in the 1940s to switch four-wire circuits and this design was further refined to serve DDD. The card sorter of the 4A/CTS allowed six digit translation of the office code number dialed by the customer. This determined the proper trunk circuits to use, where separate circuit groups were used for different cities in the area code, as in the case of Oakland. The new device used metal cards similar in principle to computer punched cards, on busy days, it sounded like a machine gun firing. CTS machines were called 4A if the translator was included in the original installation, a 1970s version of 4XB, the 4A/ETS, used a computer to translate. For international dialing, Traffic Service Position System provided the computer power. The reach of DDD was limited due to the inefficiency and expense of switching equipment, one obstacle was that the majority of switching gear did not provide Automatic Number Identification. Common control switches such as 1XB switch were fairly quickly retrofitted to provide ANI, panel switch were eventually retrofitted, as were some step-by-step that were not scheduled for immediate replacement. Even if a switch had ANI, it could not identify callers on party lines and this was only partly overcome by Tip Party Identification. As the cost of subscriber line carrier declined, party lines were phased out. In the 1960s, with the conversion still underway, plans were laid to extend Direct Dialing beyond North America. Gateway offices were set up in New York, London and Paris, the New York gateway was at 32 Avenue of the Americas. Other 5XB in the few years were installed with IDDD as original equipment
6.
India
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India, officially the Republic of India, is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and it is bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast. It shares land borders with Pakistan to the west, China, Nepal, and Bhutan to the northeast, in the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives. Indias Andaman and Nicobar Islands share a border with Thailand. The Indian subcontinent was home to the urban Indus Valley Civilisation of the 3rd millennium BCE, in the following millennium, the oldest scriptures associated with Hinduism began to be composed. Social stratification, based on caste, emerged in the first millennium BCE, early political consolidations took place under the Maurya and Gupta empires, the later peninsular Middle Kingdoms influenced cultures as far as southeast Asia. In the medieval era, Judaism, Zoroastrianism, Christianity, and Islam arrived, much of the north fell to the Delhi sultanate, the south was united under the Vijayanagara Empire. The economy expanded in the 17th century in the Mughal empire, in the mid-18th century, the subcontinent came under British East India Company rule, and in the mid-19th under British crown rule. A nationalist movement emerged in the late 19th century, which later, under Mahatma Gandhi, was noted for nonviolent resistance, in 2015, the Indian economy was the worlds seventh largest by nominal GDP and third largest by purchasing power parity. Following market-based economic reforms in 1991, India became one of the major economies and is considered a newly industrialised country. However, it continues to face the challenges of poverty, corruption, malnutrition, a nuclear weapons state and regional power, it has the third largest standing army in the world and ranks sixth in military expenditure among nations. India is a constitutional republic governed under a parliamentary system. It is a pluralistic, multilingual and multi-ethnic society and is home to a diversity of wildlife in a variety of protected habitats. The name India is derived from Indus, which originates from the Old Persian word Hindu, the latter term stems from the Sanskrit word Sindhu, which was the historical local appellation for the Indus River. The ancient Greeks referred to the Indians as Indoi, which translates as The people of the Indus, the geographical term Bharat, which is recognised by the Constitution of India as an official name for the country, is used by many Indian languages in its variations. Scholars believe it to be named after the Vedic tribe of Bharatas in the second millennium B. C. E and it is also traditionally associated with the rule of the legendary emperor Bharata. Gaṇarājya is the Sanskrit/Hindi term for republic dating back to the ancient times, hindustan is a Persian name for India dating back to the 3rd century B. C. E. It was introduced into India by the Mughals and widely used since then and its meaning varied, referring to a region that encompassed northern India and Pakistan or India in its entirety
7.
Elizabeth II
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Elizabeth II has been Queen of the United Kingdom, Canada, Australia, and New Zealand since 6 February 1952. Elizabeth was born in London as the eldest child of the Duke and Duchess of York, later King George VI and Queen Elizabeth and her father acceded to the throne on the abdication of his brother Edward VIII in 1936, from which time she was the heir presumptive. She began to undertake duties during the Second World War. Elizabeths many historic visits and meetings include a visit to the Republic of Ireland. She has seen major changes, such as devolution in the United Kingdom, Canadian patriation. She has reigned through various wars and conflicts involving many of her realms and she is the worlds oldest reigning monarch as well as Britains longest-lived. In October 2016, she became the longest currently reigning monarch, in 2017 she became the first British monarch to commemorate a Sapphire Jubilee. Elizabeth has occasionally faced republican sentiments and press criticism of the family, however, support for the monarchy remains high. Elizabeth was born at 02,40 on 21 April 1926, during the reign of her paternal grandfather and her father, Prince Albert, Duke of York, was the second son of the King. Her mother, Elizabeth, Duchess of York, was the youngest daughter of Scottish aristocrat Claude Bowes-Lyon, 14th Earl of Strathmore and she was delivered by Caesarean section at her maternal grandfathers London house,17 Bruton Street, Mayfair. Elizabeths only sibling, Princess Margaret, was born in 1930, the two princesses were educated at home under the supervision of their mother and their governess, Marion Crawford, who was casually known as Crawfie. Lessons concentrated on history, language, literature and music, Crawford published a biography of Elizabeth and Margarets childhood years entitled The Little Princesses in 1950, much to the dismay of the royal family. The book describes Elizabeths love of horses and dogs, her orderliness, others echoed such observations, Winston Churchill described Elizabeth when she was two as a character. She has an air of authority and reflectiveness astonishing in an infant and her cousin Margaret Rhodes described her as a jolly little girl, but fundamentally sensible and well-behaved. During her grandfathers reign, Elizabeth was third in the line of succession to the throne, behind her uncle Edward, Prince of Wales, and her father, the Duke of York. Although her birth generated public interest, she was not expected to become queen, many people believed that he would marry and have children of his own. When her grandfather died in 1936 and her uncle succeeded as Edward VIII, she became second-in-line to the throne, later that year, Edward abdicated, after his proposed marriage to divorced socialite Wallis Simpson provoked a constitutional crisis. Consequently, Elizabeths father became king, and she became heir presumptive, if her parents had had a later son, she would have lost her position as first-in-line, as her brother would have been heir apparent and above her in the line of succession
8.
Bristol
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Bristol is a city and county in South West England with a population of 449,300 in 2016. The district has the 10th largest population in England, while the Bristol metropolitan area is the 12th largest in the United Kingdom, the city borders North Somerset and South Gloucestershire, with the cities of Bath and Gloucester to the south-east and north-east, respectively. Iron Age hill forts and Roman villas were built near the confluence of the rivers Frome and Avon, Bristol received a royal charter in 1155 and was historically divided between Gloucestershire and Somerset until 1373, when it became a county of itself. From the 13th to the 18th century, Bristol was among the top three English cities after London in tax receipts, Bristol was surpassed by the rapid rise of Manchester, Liverpool and Birmingham in the Industrial Revolution. Bristol was a place for early voyages of exploration to the New World. On a ship out of Bristol in 1497 John Cabot, a Venetian, in 1499 William Weston, a Bristol merchant, was the first Englishman to lead an exploration to North America. At the height of the Bristol slave trade, from 1700 to 1807, the Port of Bristol has since moved from Bristol Harbour in the city centre to the Severn Estuary at Avonmouth and Royal Portbury Dock. Bristols modern economy is built on the media, electronics and aerospace industries. The city has the largest circulating community currency in the U. K. - the Bristol pound, which is pegged to the Pound sterling. It is connected to London and other major UK cities by road, rail, sea and air by the M5 and M4, Bristol Temple Meads and Bristol Parkway mainline rail stations, and Bristol Airport. The Sunday Times named it as the best city in Britain in which to live in 2014 and 2017, the most ancient recorded name for Bristol is the archaic Welsh Caer Odor, which is consistent with modern understanding that early Bristol developed between the River Frome and Avon Gorge. It is most commonly stated that the Saxon name Bricstow was a calque of the existing Celtic name, with Bric a literal translation of Odor. Alternative etymologies are supported with the numerous variations in Medieval documents with Samuel Seyer enumerating 47 alternative forms. The Old English form Brycgstow is commonly used to derive the meaning place at the bridge, utilizing another form, Brastuile, Rev. Dr. Shaw derived the name from the Celtic words bras, or braos and tuile. The poet Thomas Chatterton popularised a derivation from Brictricstow linking the town to Brictric and it appears that the form Bricstow prevailed until 1204, and the Bristolian L is what eventually changed the name to Bristol. Iron Age hill forts near the city are at Leigh Woods and Clifton Down, on the side of the Avon Gorge, a Roman settlement, Abona, existed at what is now Sea Mills, another was at the present-day Inns Court. Isolated Roman villas and small forts and settlements were scattered throughout the area. Bristol was founded by 1000, by about 1020, it was a centre with a mint producing silver pennies bearing its name
9.
Edinburgh
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Edinburgh is the capital city of Scotland and one of its 32 local government council areas. Located in Lothian on the Firth of Forths southern shore, it is Scotlands second most populous city and the seventh most populous in the United Kingdom. The 2014 official population estimates are 464,990 for the city of Edinburgh,492,680 for the authority area. Recognised as the capital of Scotland since at least the 15th century, Edinburgh is home to the Scottish Parliament and it is the largest financial centre in the UK after London. Historically part of Midlothian, the city has long been a centre of education, particularly in the fields of medicine, Scots law, literature, the sciences and engineering. The University of Edinburgh, founded in 1582 and now one of four in the city, was placed 17th in the QS World University Rankings in 2013 and 2014. The city is famous for the Edinburgh International Festival and the Fringe. The citys historical and cultural attractions have made it the United Kingdoms second most popular tourist destination after London, attracting over one million overseas visitors each year. Historic sites in Edinburgh include Edinburgh Castle, Holyrood Palace, the churches of St. Giles, Greyfriars and the Canongate, Edinburghs Old Town and New Town together are listed as a UNESCO World Heritage Site, which has been managed by Edinburgh World Heritage since 1999. It appears to derive from the place name Eidyn mentioned in the Old Welsh epic poem Y Gododdin, the poem names Din Eidyn as a hill fort in the territory of the Gododdin. The Celtic element din was dropped and replaced by the Old English burh, the first documentary evidence of the medieval burgh is a royal charter, c. 1124–1127, by King David I granting a toft in burgo meo de Edenesburg to the Priory of Dunfermline. In modern Gaelic, the city is called Dùn Èideann, the earliest known human habitation in the Edinburgh area was at Cramond, where evidence was found of a Mesolithic camp site dated to c.8500 BC. Traces of later Bronze Age and Iron Age settlements have found on Castle Rock, Arthurs Seat, Craiglockhart Hill. When the Romans arrived in Lothian at the end of the 1st century AD, at some point before the 7th century AD, the Gododdin, who were presumably descendants of the Votadini, built the hill fort of Din Eidyn or Etin. Although its location has not been identified, it likely they would have chosen a commanding position like the Castle Rock, Arthurs Seat. In 638, the Gododdin stronghold was besieged by forces loyal to King Oswald of Northumbria and it thenceforth remained under their jurisdiction. The royal burgh was founded by King David I in the early 12th century on land belonging to the Crown, in 1638, King Charles Is attempt to introduce Anglican church forms in Scotland encountered stiff Presbyterian opposition culminating in the conflicts of the Wars of the Three Kingdoms. In the 17th century, Edinburghs boundaries were defined by the citys defensive town walls
10.
Director telephone system
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In a large city there may be multiple telephone exchanges serving subscibers within the boundary of the telephone system for that city, e. g. Manchester. It would be impractical to run speech circuits from one exchange to all other exchanges within the city so an alternative arrangement is used. Certain exchanges will be used to switch calls going to a different to that of the calling party thus acting as a hub for these calls. These exchanges wil be interconnected to other acting as hubs. Depending on the exchange of the calling and called parties the call may be routed via one or more hubs to get to its destination and this routing was invisible to the subsciber who always dialled the same number wherever he was on the system within that city. The Director telephone system was a development of the Strowger step-by-step switching system used in London, a large proportion of telephone traffic in large metropolitan areas is outgoing traffic, and it is distributed over many exchanges. A non-Director SXS exchange system is not suitable for these areas, customer stations were assigned seven-digit numbers, with the first three digits spelling out the local exchange name, this expedited call handling particularly to and from manual exchanges. The translated digits were sent to the selectors, and then the four numeric digits were sent to three switching stages in the terminating exchange. Subscriber telephone numbers were seven digit numbers, with the first three digits corresponding to the first three letters of the exchange name. The translation map of letters to digits was displayed directly on the rotary dial. The British letter arrangement was similar to American dials, except that the letters “O” mapped to digit 0, the mapping of O and Q to 0 was to eliminate the possibility of a subscriber misdialling as a result of misreading a number. A subscriber in Wimbledon would be assigned the number WIMbledon1234, the first three letters, written in capitals, indicated the exchange code to be dialled, the actual trains of pulses from the subscribers dial were 9461234. The exchange code digits dialled by the calling subscriber were the same from any telephone in the London director area, subscribers on manual exchanges asked for a number in the format Wimbledon1234, whether the called number was on a manual or automatic exchange. The three-letter code was written in bold if the caller should dial all seven digits. If an exchange was outside the Director linked-number area, the name and number was in small type. Special Service numbers apart from “0” for operator used an exchange name, e. g. TOL, TRU, DIR, TIM, ENG, UMP. To make a call, the subscribers uniselector seizes a free 1st code selector, the A-digit selector returns dial tone, steps to the first dialled digit and searches for a free director from that group. The director includes a two-motion selector - the BC switch - which steps vertically, the pulse train output begins after the C-digit is received from the subscribers telephone
11.
Republic of Ireland
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Ireland, also known as the Republic of Ireland, is a sovereign state in north-western Europe occupying about five-sixths of the island of Ireland. The capital and largest city is Dublin, which is located on the part of the island. The state shares its land border with Northern Ireland, a part of the United Kingdom. It is otherwise surrounded by the Atlantic Ocean, with the Celtic Sea to the south, Saint Georges Channel to the south-east, and it is a unitary, parliamentary republic. The head of government is the Taoiseach, who is elected by the Dáil and appointed by the President, the state was created as the Irish Free State in 1922 as a result of the Anglo-Irish Treaty. It was officially declared a republic in 1949, following the Republic of Ireland Act 1948, Ireland became a member of the United Nations in December 1955. It joined the European Economic Community, the predecessor of the European Union, after joining the EEC, Ireland enacted a series of liberal economic policies that resulted in rapid economic growth. The country achieved considerable prosperity between the years of 1995 and 2007, which known as the Celtic Tiger period. This was halted by a financial crisis that began in 2008. However, as the Irish economy was the fastest growing in the EU in 2015, Ireland is again quickly ascending league tables comparing wealth and prosperity internationally. For example, in 2015, Ireland was ranked as the joint sixth most developed country in the world by the United Nations Human Development Index and it also performs well in several national performance metrics, including freedom of the press, economic freedom and civil liberties. Ireland is a member of the European Union and is a member of the Council of Europe. The 1922 state, comprising 26 of the 32 counties of Ireland, was styled, the Constitution of Ireland, adopted in 1937, provides that the name of the State is Éire, or, in the English language, Ireland. Section 2 of the Republic of Ireland Act 1948 states, It is hereby declared that the description of the State shall be the Republic of Ireland. The 1948 Act does not name the state as Republic of Ireland, because to have done so would have put it in conflict with the Constitution. The government of the United Kingdom used the name Eire, and, from 1949, Republic of Ireland, for the state, as well as Ireland, Éire or the Republic of Ireland, the state is also referred to as the Republic, Southern Ireland or the South. In an Irish republican context it is referred to as the Free State or the 26 Counties. From the Act of Union on 1 January 1801, until 6 December 1922, during the Great Famine, from 1845 to 1849, the islands population of over 8 million fell by 30%
12.
Telephone numbers in the United Kingdom
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Telephone numbers in the United Kingdom are administered by the UK governments Office of Communications. For this purpose Ofcom established a telephone numbering plan, known as the National Telephone Numbering Plan, since 28 April 2001, almost all geographic numbers and most non-geographic numbers have 9 or 10 national numbers after the 0 trunk code. All mobile telephone numbers have 10 national numbers after the 0 trunk code, regions with shorter area codes, typically large cities, permit the allocation of more telephone numbers as the local number portion has more digits. Local customer numbers are four to eight figures long, the total number of digits is ten, but in a very few areas the total may be nine digits. The area code is referred to as an STD or a dialling code in the UK. The code allocated to the largest population is for London, the code allocated to the largest area is for all of Northern Ireland. The UK Numbering Plan also applies to three British Crown dependencies—Jersey, Guernsey and the Isle of Man—even though they are not part of the UK itself. Possible number formats for UK telephone numbers are as follows, Number ranges starting 01 can have NSN length as 10 or 9 digits, the 0800 range can have NSN length as 10,9 or 7 digits. The 0845 range can have NSN length as 10 or 7 digits, the 0500 range has NSN length as 9 digits only. There are no numbers in the UK with an NSN length of 8 digits. Geographic telephone numbers in the UK always have nine or ten digits, four-digit area codes have either six-digit subscriber numbers or a mix of five- and six-digit subscriber numbers. Xxxxxx This is the used by most areas. It has an area code and a six digit subscriber number. These area codes were changed by adding a 1 directly after the zero as a part of PhONEday in 1995. Just short of 581 areas use this format, and the area range from 01200 to 01998. A small number of areas also have a few subscriber numbers that have only five digits. That is, almost all area codes now have only six digit local numbers, six of the four-digit area codes are known as mixed areas as they share those four digits with the twelve five-digit area codes. The numbers therefore have only nine digits after the initial zero trunk code and these area codes were changed by adding a 1 directly after the initial zero as a part of PhONEday in 1995
13.
Telephone numbers in India
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Subscriber Trunk Dialling codes are assigned to each city/town/village, with the larger Metro cities having shorter area codes, the shortest being 2 digits. Land line numbers are at most 8 digits long, the total length of all phone numbers in India is constant at 10 digits, for example 7513200000 signifies a STD code i. e.751 Gwalior & the phone number 3200000. Due to the availability of multiple operators offering fixed line services, there is an operator-code for each telephone number, no prefix is required to call from one landline to another in the same STD area. A prefix of 0+STD code is required to dial from a phone in one STD code area to another. A prefix of 0+STD code is required to dial from a phone in India to any landline number, irrespective of STD area. g. to dial Delhi from Gurgaon. This feature was stopped with effect from 00,00 hours of 10 March 2009, a typical mobile number in India is +91-XX-XXX-XXXXX. Where the first two digits indicate a system, the next three denote the mobile switching code while the remaining five digits are unique to the subscriber. Short codes are five digits in length and have to start with the digit 5 like 58888 as of 2007, previously, they were four-digit in number and could be of any combination, like 8888 or 7827. The current five digits can be extended by three digits further representing 3 additional characters. Messages sent to these Short Codes are commonly referred to as Premium Rate SMS Messages and cost from Rs.3 to Rs.6 per message depending on the operator as well as the service and the company. Telemarketers have been issued 10-digit telephone numbers starting with 140 by the Department of Telecommunications on TRAIs request, Department of Telecommunications, Government of India Telecom Regulatory Authority of India India National Numbering Plan of 2003
14.
Telephone numbers in Australia
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The Australian telephone numbering plan describes the allocation of phone numbers in Australia. It has changed many times, the most recent major reorganisation by the Australian Communications, for landline telephony, Australia is now geographically divided into four large areas, most of which cover more than one State and/or Territory. All Local telephone numbers within these four areas are of eight digits, the National Significant Number consists of a single digit Area code followed by the Local eight digit number - a total of ten digits. Thus, the Full National Number has ten digits, 0x xxxx xxxx, the Australian Trunk Access Code and the following digit specify the type of service required. The following is a high level listing of the numbering plan, the current numbering plan would appear to be sufficient to cope with potential increase in demand for services for quite some time to come. The 06 and 09 area codes are completely unused, in addition, each current area code has large number ranges unallocated. When dialling from outside Australia it is necessary to dial the Country Code for Australia followed by the nine digit National Significant Number, some numbers beginning with a 1 may be dialled without any replacement, after dialling the required International Access Code and the Country Code for Australia. Australian Local Area numbers are of eight digits in length, conventionally written in the form xxxx xxxx, Mobile numbers are conventionally written 04xx xxx xxx. If a landline or mobile number is written where it may be viewed by an international audience then the number is written as +61 x xxxx xxxx or +61 4xx xxx xxx respectively. Fixed line telephone numbers in Australia exist within four areas, each specified by a single area code. In major centres, the first four digits specify the CCA, smaller Exchanges in more remote areas may be specified by five or six local digits, meaning that no more than 1,000 or 100 numbers respectively could be connected to such exchanges. To access numbers in the area, it is necessary only to dial the eight digits concerned. To access a number in another Area it is firstly to dial the Trunk Access Code of 0, followed by the area code. The area codes do not exactly match State/Territory boundaries, notable are the part of New South Wales around Broken Hill, which uses 80xx numbers, and Wodonga, which is in Victoria but is within the New South Wales area code. Landlines use an open dialling plan, if the callers phone shares the same code as the called phone. For example, a call from the number 55515678, to the number 70101111, similarly, a person who dials 70105678 on a land-line or mobile phone in Melbourne will be connected to 0370105678. For this reason, landline numbers are often specified without the area code, if a persons number and the destination number share the same area code, then the area code is not required, even if it is not a local call. However, the Full National Number may always be dialled, within Australia, Mobile phone numbers traditionally begin with 04 - the Australian National Trunk Access Code 0, plus the Mobile indicator 4 - followed by eight digits
15.
Telecommunication
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Telecommunication is the transmission of signs, signals, messages, writings, images and sounds or intelligence of any nature by wire, radio, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology and it is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are divided into communication channels which afford the advantages of multiplexing. The term is used in its plural form, telecommunications. Early means of communicating over a distance included visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, other examples of pre-modern long-distance communication included audio messages such as coded drumbeats, lung-blown horns, and loud whistles. Zworykin, John Logie Baird and Philo Farnsworth, the word telecommunication is a compound of the Greek prefix tele, meaning distant, far off, or afar, and the Latin communicare, meaning to share. Its modern use is adapted from the French, because its use was recorded in 1904 by the French engineer. Communication was first used as an English word in the late 14th century, in the Middle Ages, chains of beacons were commonly used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could pass a single bit of information. One notable instance of their use was during the Spanish Armada, in 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system between Lille and Paris. However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres, as a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880. Homing pigeons have occasionally used throughout history by different cultures. Pigeon post is thought to have Persians roots and was used by the Romans to aid their military, frontinus said that Julius Caesar used pigeons as messengers in his conquest of Gaul. The Greeks also conveyed the names of the victors at the Olympic Games to various cities using homing pigeons, in the early 19th century, the Dutch government used the system in Java and Sumatra. And in 1849, Paul Julius Reuter started a service to fly stock prices between Aachen and Brussels, a service that operated for a year until the gap in the telegraph link was closed. Sir Charles Wheatstone and Sir William Fothergill Cooke invented the telegraph in 1837. Also, the first commercial electrical telegraph is purported to have constructed by Wheatstone and Cooke. Both inventors viewed their device as an improvement to the electromagnetic telegraph not as a new device, samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837
16.
History of telecommunication
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The history of telecommunication began with the use of smoke signals and drums in Africa, the Americas and parts of Asia. In the 1790s, the first fixed semaphore systems emerged in Europe and this article details the history of telecommunication and the individuals who helped make telecommunication systems what they are today. The history of telecommunication is an important part of the history of communication. Early telecommunications included smoke signals and drums, talking drums were used by natives in Africa, New Guinea and South America, and smoke signals in North America and China. Contrary to what one might think, these systems were used to do more than merely announce the presence of a military camp. In Rabbinical Judaism a signal was given by means of kerchiefs or flags at intervals along the way back to the high priest to indicate the goat for Azazel had been pushed from the cliff, greek hydraulic semaphore systems were used as early as the 4th century BC. The hydraulic semaphores, which worked with water filled vessels and visual signals, however, they could only utilize a very limited range of pre-determined messages, and as with all such optical telegraphs could only be deployed during good visibility conditions. During the Middle Ages, chains of beacons were used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could pass a single bit of information. One notable instance of their use was during the Spanish Armada, french engineer Claude Chappe began working on visual telegraphy in 1790, using pairs of clocks whose hands pointed at different symbols. These did not prove quite viable at long distances, and Chappe revised his model to use two sets of jointed wooden beams, operators moved the beams using cranks and wires. He built his first telegraph line between Lille and Paris, followed by a line from Strasbourg to Paris, in 1794, a Swedish engineer, Abraham Edelcrantz built a quite different system from Stockholm to Drottningholm. As opposed to Chappes system which involved pulleys rotating beams of wood, however semaphore as a communication system suffered from the need for skilled operators and expensive towers often at intervals of only ten to thirty kilometres. As a result, the last commercial line was abandoned in 1880, experiments on communication with electricity, initially unsuccessful, started in about 1726. Scientists including Laplace, Ampère, and Gauss were involved, both their designs employed multiple wires in order to visually represent almost all Latin letters and numerals. Thus, messages could be conveyed electrically up to a few kilometers, the telegraph receivers operator would visually observe the bubbles and could then record the transmitted message, albeit at a very low baud rate. The first working telegraph was built by Francis Ronalds in 1816, Charles Wheatstone and William Fothergill Cooke patented a five-needle, six-wire system, which entered commercial use in 1838. It used the deflection of needles to represent messages and started operating over twenty-one kilometres of the Great Western Railway on 9 April 1839, both Wheatstone and Cooke viewed their device as an improvement to the electromagnetic telegraph not as a new device
17.
Beacon
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A beacon is an intentionally conspicuous device designed to attract attention to a specific location. When used in fashion, beacons can be considered a form of optical telegraphy. Beacons help guide navigators to their destinations, types of navigational beacons include radar reflectors, radio beacons, sonic and visual signals. Visual beacons range from small, single-pile structures to large lighthouses or light stations, lighted beacons are called lights, unlighted beacons are called daybeacons. As signals, beacons are an ancient form of telegraph and were part of a relay league. Systems of this kind have existed for centuries over much of the world, the ancient Romans used beacons and beacons figure on several occasions on the column of Trajan. It was devised by Leo the Mathematician for Emperor Theophilos, but either abolished or radically curtailed by Theophilos son and successor, Michael III. Beacons were later used in Greece as well, while the parts of the beacon system in Anatolia seem to have been reactivated in the 12th century by Emperor Manuel I Komnenos. In Scandinavia many hill forts were part of networks to warn against invading pillagers. In Finland, these beacons were called vainovalkeat, persecution fires, or vartiotulet, guard fires, in Wales, the Brecon Beacons were named for beacons used to warn of approaching English raiders. In England, the most famous examples are the used in Elizabethan England to warn of the approaching Spanish Armada. Many hills in England were named Beacon Hill after such beacons, in the Scottish borders country, a system of beacon fires was at one time established to warn of incursions by the English. Hume and Eggerstone castles and Soltra Edge were part of this network, the Great Wall of China is also a beacon network. In Spain, the border of Granada in the territory of the Crown of Castile had a beacon network to warn against Moorish raiders. Vehicular beacons are rotating or flashing lights affixed to the top of a vehicle to attract the attention of surrounding vehicles, emergency vehicles such as fire engines, ambulances, police cars, tow trucks, construction vehicles, and snow-removal vehicles carry beacon lights. Beacons may be constructed with halogen bulbs similar to those used in vehicle headlamps, xenon flashtubes, incandescent and xenon light sources require the vehicle’s engine to continue running to ensure that the battery is not depleted when the lights are used for a prolonged period. The low power consumption of LEDs allows the engine to remain turned off while the lights operate nodes. Beacons and bonfires are used to mark occasions and celebrate events
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History of broadcasting
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The first broadcasting of a radio transmission consisted of Morse code was made from a temporary station set up by Guglielmo Marconi in 1895. This followed on from pioneering work in the field by Alessandro Volta, André-Marie Ampère, Georg Ohm, James Clerk Maxwell, the broadcasting of music and talk via radio started experimentally around 1905-1906, and commercially around 1920 to 1923. VHF stations started 30 to 35 years later, when people started broadcasting television the first movie that was shown was Batman curse of the green pearl it was 10 minutes long. In Britain this system was known as Electrophone, and was available as early as 1895 or 1899, in Hungary, it was called Telefon Hírmondó, and in France, Théâtrophone ). The Wikipedia Telefon Hírmondó page includes a 1907 program guide which looks similar to the types of schedules used by many broadcasting stations some 20 or 30 years later. By the 1950s, virtually every country had a broadcasting system, today, most countries have evolved into a dual system, including the UK. By 1955, practically every family in North America and Western Europe, a dramatic change came in the 1960s with the introduction of small inexpensive portable transistor radio, the greatly expanded ownership and usage. Access became practically universal across the world, Australia developed its own system, through its own engineers, manufacturers, retailers, newspapers, entertainment services, and news agencies. The government set up the first radio system, and business interests marginalized the hobbyists, the Labor Party was especially interested in radio because it allowed them to bypass the newspapers, which were mostly controlled by the opposition. Both parties agreed on the need for a system, and in 1932 set up the Australian Broadcasting Commission. The first commercial broadcasters, originally known as B class stations, were on the air as early as 1925, the number of stations remained relatively dormant throughout World War II and in the post-war era. The broadcasting system was deregulated in 1992, except that there were limits on foreign ownership. By 2000,99 percent of Australians owned at least one television set, Australian radio hams can be traced to the early 1900s. The 1905 Wireless Telegraphy Act whilst acknowledging the existence of wireless telgraphy, in 1906, the first official Morse code transmission in Australia was by the Marconi Company between Queenscliff, Victoria and Devonport, Tasmania. The first broadcast of music was made during a demonstration on 13 August 1919 by Ernest Fisk of AWA – Amalgamated Wireless, a number of amateurs commenced broadcasting music in 1920 and 1921. 2CM was run by Charles MacLuran who started the station in 1921 with regular Sunday evening broadcasts from the Wentworth Hotel, 2CM is often regarded as Australias first, regular, non-official station. It was not until November 1923 when the government finally gave its approval for a number of officially recognised medium wave stations, all stations operated under a unique Sealed Set system under which each set was sealed to the frequency of one station. Part of the price of the set went to the government via the Postmaster-Generals Department, apart from extremely limited advertising, this was the broadcasters only source of income
19.
Cable television
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This contrasts with broadcast television, in which the television signal is transmitted over the air by radio waves and received by a television antenna attached to the television. FM radio programming, high-speed Internet, telephone services, and similar non-television services may also be provided through these cables, analog television was standard in the 20th century, but since the 2000s, cable systems have been upgraded to digital cable operation. A cable channel is a television network available via cable television, alternative terms include non-broadcast channel or programming service, the latter being mainly used in legal contexts. Examples of cable/satellite channels/cable networks available in many countries are HBO, MTV, Cartoon Network, E. Eurosport, the abbreviation CATV is often used for cable television. It originally stood for Community Access Television or Community Antenna Television, in areas where over-the-air TV reception was limited by distance from transmitters or mountainous terrain, large community antennas were constructed, and cable was run from them to individual homes. The origins of cable broadcasting for radio are even older as radio programming was distributed by cable in some European cities as far back as 1924, Cable television has gone through a series of steps of evolution in the United States and Canada. Particularly in Canada, communities with their own signals were fertile cable markets, as viewers wanted to receive American signals. Early systems carried only a maximum of seven channels, using 2,4,5 or 6,7,9,11 and 13, as the equipment was unable to confine the signal discreetly within the assigned channel bandwidth. The reason 4 and 5 along with 6 and 7 could be used together was because of the 4 MHz gap between 4 and 5 and the nearly 90 MHz gap between 6 and 7. Even though eight channels are listed, in systems that maximized 7 channels. As equipment improved, all channels could be utilized, except where a local VHF television station broadcast. Local broadcast channels were not usable for signals deemed to be priority, later, the cable operators began to carry FM radio stations, and encouraged subscribers to connect their FM stereo sets to cable. Before stereo and bilingual TV sound became common, Pay-TV channel sound was added to the FM stereo cable line-ups, about this time, operators expanded beyond the 12-channel dial to use the midband and superband VHF channels adjacent to the high band 7-13 of North American television frequencies. Some operators as in Cornwall, Ontario, used a dual distribution network with Channels 2-13 on each of the two cables, during the 1980s, United States regulations not unlike public, educational, and government access created the beginning of cable-originated live television programming. These stations evolved partially into todays over-the-air digital subchannels, where a main broadcast TV station e. g, many live local programs with local interests were subsequently created all over the United States in most major television markets in the early 1980s. This evolved into todays many cable-only broadcasts of diverse programming, including cable-only produced television movies and miniseries, Cable specialty channels, starting with channels oriented to show movies and large sporting or performance events, diversified further, and narrowcasting became common. By the late 1980s, cable-only signals outnumbered broadcast signals on cable systems, by the mid-1980s in Canada, cable operators were allowed by the regulator to enter into distribution contracts with cable networks on their own. By the 1990s, tiers became common, with customers able to subscribe to different tiers to obtain different selections of additional channels above the basic selection, by subscribing to additional tiers, customers could get specialty channels, movie channels, and foreign channels
20.
Communications satellite
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Communications satellites are used for television, telephone, radio, internet, and military applications. There are over 2,000 communications satellites in Earth’s orbit, Wireless communication uses electromagnetic waves to carry signals. These waves require line-of-sight, and are thus obstructed by the curvature of the Earth, the purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated points. Communications satellites use a range of radio and microwave frequencies. To avoid signal interference, international organizations have regulations for which frequency ranges or bands certain organizations are allowed to use and this allocation of bands minimizes the risk of signal interference. The concept of the communications satellite was first proposed by Arthur C. Clarke, building on work by Konstantin Tsiolkovsky and on the 1929 work by Herman Potočnik Das Problem der Befahrung des Weltraums — der Raketen-motor, in October 1945 Clarke published an article titled Extraterrestrial Relays in the British magazine Wireless World. The article described the fundamentals behind the deployment of artificial satellites in geostationary orbits for the purpose of relaying radio signals, thus, Arthur C. Clarke is often quoted as being the inventor of the communications satellite and the term Clarke Belt employed as a description of the orbit. Decades later a project named Communication Moon Relay was a project carried out by the United States Navy. Its objective was to develop a secure and reliable method of communication by using the Moon as a passive reflector. The first artificial Earth satellite was Sputnik 1, put into orbit by the Soviet Union on October 4,1957, it was equipped with an on-board radio-transmitter that worked on two frequencies,20.005 and 40.002 MHz. Sputnik 1 was launched as a step in the exploration of space, while incredibly important it was not placed in orbit for the purpose of sending data from one point on earth to another. And it was the first artificial satellite in the leading to todays satellite communications. The first artificial satellite used solely to further advances in communications was a balloon named Echo 1. Echo 1 was the worlds first artificial communications satellite capable of relaying signals to other points on Earth and it soared 1,600 kilometres above the planet after its Aug.12,1960 launch, yet relied on humanitys oldest flight technology — ballooning. Launched by NASA, Echo 1 was a 30-metre aluminized PET film balloon served as a passive reflector for radio communications. The worlds first inflatable satellite — or satelloon, as they were informally known — helped lay the foundation of todays satellite communications, the idea behind a communications satellite is simple, Send data up into space and beam it back down to another spot on the globe. Echo 1 accomplished this by serving as an enormous mirror,10 stories tall
21.
Computer network
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A computer network or data network is a telecommunications network which allows nodes to share resources. In computer networks, networked computing devices exchange data with other using a data link. The connections between nodes are established using either cable media or wireless media, the best-known computer network is the Internet. Network computer devices that originate, route and terminate the data are called network nodes, nodes can include hosts such as personal computers, phones, servers as well as networking hardware. Two such devices can be said to be networked together when one device is able to exchange information with the other device, Computer networks differ in the transmission medium used to carry their signals, communications protocols to organize network traffic, the networks size, topology and organizational intent. In most cases, application-specific communications protocols are layered over other more general communications protocols and this formidable collection of information technology requires skilled network management to keep it all running reliably. The chronology of significant computer-network developments includes, In the late 1950s, in 1960, the commercial airline reservation system semi-automatic business research environment went online with two connected mainframes. Licklider developed a group he called the Intergalactic Computer Network. In 1964, researchers at Dartmouth College developed the Dartmouth Time Sharing System for distributed users of computer systems. The same year, at Massachusetts Institute of Technology, a group supported by General Electric and Bell Labs used a computer to route. Throughout the 1960s, Leonard Kleinrock, Paul Baran, and Donald Davies independently developed network systems that used packets to transfer information between computers over a network, in 1965, Thomas Marill and Lawrence G. Roberts created the first wide area network. This was an precursor to the ARPANET, of which Roberts became program manager. Also in 1965, Western Electric introduced the first widely used telephone switch that implemented true computer control, in 1972, commercial services using X.25 were deployed, and later used as an underlying infrastructure for expanding TCP/IP networks. In July 1976, Robert Metcalfe and David Boggs published their paper Ethernet, Distributed Packet Switching for Local Computer Networks, in 1979, Robert Metcalfe pursued making Ethernet an open standard. In 1976, John Murphy of Datapoint Corporation created ARCNET, a network first used to share storage devices. In 1995, the transmission speed capacity for Ethernet increased from 10 Mbit/s to 100 Mbit/s, by 1998, Ethernet supported transmission speeds of a Gigabit. Subsequently, higher speeds of up to 100 Gbit/s were added, the ability of Ethernet to scale easily is a contributing factor to its continued use. Providing access to information on shared storage devices is an important feature of many networks, a network allows sharing of files, data, and other types of information giving authorized users the ability to access information stored on other computers on the network
22.
Drums in communication
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Developed and used by cultures living in forested areas, drums served as an early form of long-distance communication, and were used during ceremonial and religious functions. While this type of hour-glass shaped instrument can be modulated quite closely, its range is limited to a gathering or market-place, ceremonial functions could include dance, rituals, story-telling and communication of points of order. Message drums, or more properly slit gongs, with chambers and long. Variations in the thickness of the walls would vary the tones when struck by heavy wooden drum sticks, while some were simple utilitarian pieces they could also be highly elaborate works of sculpture while still retaining their function. Often there are small stands under each end of the drum to keep it off of the ground and these drums were made out of hollowed logs. The bigger the log, the sound would be made. A long slit would be cut in one side of the tree trunk, next, the log would be hollowed out through the slit, leaving lips on each side of the opening. A drum could be tuned to produce a note and a higher note. For that it would need to be hollowed out more under one lip than under the other, the drums lips are hit with sticks, beating out rhythms of high and low notes. Under ideal conditions, the sound can be understood at 3 to 7 miles, the talking drums or jungle drums is also a euphemism for gossip – similar to the grapevine. In Africa, New Guinea and the tropical America, people have used drum telegraphy to communicate each other from far away for centuries. An African message can be transmitted at the speed of 100 miles in an hour, among the famous communication drums are the drums of West Africa. From regions known today as Nigeria and Ghana they spread across West Africa and to America, there they were banned because they were being used by the slaves to communicate over long distances in a code unknown to their enslavers. Talking drums were used in East Africa and are described by Andreus Bauer in the Street of Caravans while acting as security guard in the Wissmann Truppe for the caravan of Charles Stokes. The traditional drumming found in Africa is actually of three different types, firstly, a rhythm can represent an idea. Secondly it can repeat the accentual profile of an utterance or thirdly it can simply be subject to musical laws. Drum communication methods are not languages in their own right, they are based on actual natural languages, the sounds produced are conventionalized or idiomatic signals based on speech patterns. The messages are normally very stereotyped and context-dependent and they lack the ability to form new combinations and expressions
23.
Electrical telegraph
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An electrical telegraph is a telegraph that uses electrical signals, usually conveyed via dedicated telecommunication lines or radio. From early studies of electricity, electrical phenomena were known to travel with great speed, in 1753 an anonymous writer in the Scots Magazine suggested an electrostatic telegraph. In 1774 Georges-Louis Le Sage realised an early electric telegraph, the telegraph had a separate wire for each of the 26 letters of the alphabet and its range was only between two rooms of his home. In 1800 Alessandro Volta invented the voltaic pile, allowing for a current of electricity for experimentation. Both their designs employed multiple wires to represent almost all Latin letters, thus, messages could be conveyed electrically up to a few kilometers, with each of the telegraph receivers wires immersed in a separate glass tube of acid. The telegraph receivers operator would watch the bubbles and could record the transmitted message. This is in contrast to later telegraphs that used a single wire, hans Christian Ørsted discovered in 1820 that an electric current produces a magnetic field which will deflect a compass needle. In the same year Johann Schweigger invented the galvanometer, with a coil of wire around a compass, in 1824, Peter Barlow said that such a system only worked to a distance of about 200 feet, and so was impractical. In 1825 William Sturgeon invented the electromagnet, with a winding of uninsulated wire on a piece of varnished iron. During his tenure at The Albany Academy from 1826 to 1832, in 1835 Joseph Henry and Edward Davy invented the critical electrical relay. Davys relay used a needle which dipped into a mercury contact when an electric current passed through the surrounding coil. This allowed a weak current to switch a larger current to operate a powerful local electromagnet over very long distances, Davy demonstrated his telegraph system in Regents Park in 1837 and was granted a patent on 4 July 1838. He also developed an electric relay, the first working telegraph was built by the English inventor Francis Ronalds in 1816 and used static electricity. At the family home on Hammersmith Mall, he set up a subterranean system in a 175 yard long trench as well as an eight mile long overhead telegraph. The lines were connected at both ends to revolving dials marked with the letters of the alphabet and electrical impulses sent along the wire were used to transmit messages, offering his invention to the Admiralty in July 1816, it was rejected as “wholly unnecessary”. Elements of Ronalds’ design were utilised in the subsequent commercialisation of the telegraph over 20 years later, the telegraph invented by Baron Schilling von Canstatt in 1832 had a transmitting device which consisted of a keyboard with 16 black-and-white keys. These served for switching the electric current, the receiving instrument consisted of six galvanometers with magnetic needles, suspended from silk threads. Both stations of Shillings telegraph were connected by eight wires, six were connected with the galvanometers, one served for the return current, when at the starting station the operator pressed a key, the corresponding pointer was deflected at the receiving station
24.
Fax
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Fax, sometimes called telecopying or telefax, is the telephonic transmission of scanned printed material, normally to a telephone number connected to a printer or other output device. The receiving fax machine interprets the tones and reconstructs the image, early systems used direct conversions of image darkness to audio tone in a continuous or analog manner. Since the 1980s, most machines modulate the audio frequencies using a digital representation of the page which is compressed to quickly transmit areas which are all-white or all-black. Scottish inventor Alexander Bain worked on chemical mechanical fax type devices and he received British patent 9745 on May 27,1843 for his Electric Printing Telegraph. Frederick Bakewell made several improvements on Bains design and demonstrated a telefax machine, the Pantelegraph was invented by the Italian physicist Giovanni Caselli. He introduced the first commercial service between Paris and Lyon in 1865, some 11 years before the invention of the telephone. In 1880, English inventor Shelford Bidwell constructed the scanning phototelegraph that was the first telefax machine to scan any two-dimensional original, previously, photographs had been sent over the radio using this process. The Western Union Deskfax fax machine, announced in 1948, was a machine that fit comfortably on a desktop. As a designer for the Radio Corporation of America, in 1924, Richard H. Ranger invented the wireless photoradiogram, or transoceanic radio facsimile, the forerunner of today’s fax machines. A photograph of President Calvin Coolidge sent from New York to London on November 29,1924 became the first photo picture reproduced by transoceanic radio facsimile, commercial use of Ranger’s product began two years later. Also in 1924, Herbert E. Ives of AT&T Corporation transmitted and reconstructed the first color facsimile, around 1952 or so, Finch Facsimile, a highly developed machine, was described in detail in a book, it was never manufactured in quantity. By the late 1940s, radiofax receivers were sufficiently miniaturized to be fitted beneath the dashboard of Western Unions Telecar telegram delivery vehicles, in the 1960s, the United States Army transmitted the first photograph via satellite facsimile to Puerto Rico from the Deal Test Site using the Courier satellite. Radio fax is still in limited use today for transmitting weather charts, in 1964, Xerox Corporation introduced what many consider to be the first commercialized version of the modern fax machine, under the name or Long Distance Xerography. This model was superseded two years later with a unit that would set the standard for fax machines for years to come. Up until this point facsimile machines were expensive and hard to operate. In 1966, Xerox released the Magnafax Telecopiers, a smaller and this unit was far easier to operate and could be connected to any standard telephone line. This machine was capable of transmitting a letter-sized document in about six minutes, the first sub-minute, digital fax machine was developed by Dacom, which built on digital data compression technology originally developed at Lockheed for satellite communication. By the late 1970s, many companies around the world, entered the fax market, very shortly after a new wave of more compact, faster and efficient fax machines would hit the market
25.
Heliograph
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A heliograph is a wireless solar telegraph that signals by flashes of sunlight reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter, the heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century. Its main uses were military, survey and forest protection work, heliographs were standard issue in the British and Australian armies until the 1960s, and were used by the Pakistani army as late as 1975. Most heliographs were variants of the British Army Mance Mark V version and it used a mirror with a small unsilvered spot in the centre. The sender aligned the heliograph to the target by looking at the target in the mirror. Keeping his head still, he adjusted the aiming rod so its cross wires bisected the target. This indicated that the sunbeam was pointing at the target, the flashes were produced by a keying mechanism that tilted the mirror up a few degrees at the push of a lever at the back of the instrument. If the sun was in front of the sender, its rays were reflected directly from this mirror to the receiving station. If the sun was behind the sender, the rod was replaced by a second mirror, to capture the sunlight from the main mirror. The U. S. Signal Corps heliograph mirror did not tilt and this type produced flashes by a shutter mounted on a second tripod. The heliograph had some great advantages, however, anyone in the beam with the correct knowledge could intercept signals without being detected. In the Boer War, where both sides used heliographs, tubes were used to decrease the dispersion of the beam.5 degrees to 15 degrees. The distance that signals could be seen depended on the clarity of the sky. A clear line of sight was required, and since the Earths surface is curved, under ordinary conditions, a flash could be seen 30 miles with the naked eye, and much farther with a telescope. The maximum range was considered to be 10 miles for each inch of mirror diameter, mirrors ranged from 1.5 inches to 12 inches or more. The record distance was established by a detachment of U. S, the German professor Carl Friedrich Gauss of the University of Göttingen developed and used a predecessor of the heliograph in 1821. His device directed a beam of sunlight to a distant station to be used as a marker for geodetic survey work. Similarly, the story that a shield was used as a heliograph at the Battle of Marathon is a modern myth, what Herodotus did write was that someone was accused of having arranged to hold up a shield as a signal
26.
Hydraulic telegraph
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A hydraulic telegraph is either of two different hydraulic-telegraph telecommunication systems. The earliest one was developed in 4th century BC Greece, while the one was developed in 19th century AD Britain. The Greek system was deployed in combination with semaphoric fires, while the latter British system was operated purely by hydraulic fluid pressure, although both systems employed water in their sending and receiver devices, their transmission media were completely different. The ancient Greek system transmitted its semaphoric information to the receiver visually, while the Greek device was extremely limited in the codes it could convey, the British device was never deployed in operation other than for very short-distance demonstrations. The ancient Greek design was described in the 4th century BC by Aeneas Tacticus, according to Polybius, it was used during the First Punic War to send messages between Sicily and Carthage. The system involved identical containers on separate hills, which are not connected to other, each container would be filled with water. The rods were inscribed with various predetermined codes at various points along its height, water would drain out until the water level reached the desired code, at which point the sender would lower his torch, and the operators would simultaneously close their spigots. Thus the length of time the torch was visible could be correlated with specific predetermined codes and messages. A contemporary description of the ancient telegraphic method was provided by Polybius, the system was estimated to cost £200 per mile and could convey a vocabulary of 12,000 words. The U. K. s Mechanics Magazine in March 1838 described it as follows, hydraulic telegraph may supersede the semaphore and the galvanic telegraph. Byzantine beacon system Fryctoria Heliograph Optical communication Signal lamp Telegraph Connected Earth
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History of the Internet
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The history of the Internet begins with the development of electronic computers in the 1950s. Initial concepts of packet networking originated in several science laboratories in the United States, United Kingdom. The US Department of Defense awarded contracts as early as the 1960s for packet network systems, including the development of the ARPANET. Packet switching networks such as ARPANET, NPL network, CYCLADES, Merit Network, Tymnet, Donald Davies first designed a packet-switched network at the National Physics Laboratory in the UK, which became a testbed for UK research for almost two decades. The ARPANET project led to the development of protocols for internetworking, Access to the ARPANET was expanded in 1981 when the National Science Foundation funded the Computer Science Network. In 1982, the Internet protocol suite was introduced as the networking protocol on the ARPANET. Commercial Internet service providers began to emerge in the very late 1980s, the ARPANET was decommissioned in 1990. The research and education community continues to develop and use advanced networks such as NSFs very high speed Backbone Network Service, Internet2, increasing amounts of data are transmitted at higher and higher speeds over fiber optic networks operating at 1-Gbit/s, 10-Gbit/s, or more. Today the Internet continues to grow, driven by ever greater amounts of information, commerce, entertainment. Such communication systems were limited to point to point communication between two end devices. Telegraph systems and telex machines can be considered precursors of this kind of communication. The Telegraph in the late 19th century was the first fully digital communication system, fundamental theoretical work in data transmission and information theory was developed by Claude Shannon, Harry Nyquist, and Ralph Hartley in the early 20th century. Early computers had a processing unit and remote terminals. As the technology evolved, new systems were devised to allow communication over longer distances or with higher speed that were necessary for the computer model. These technologies made it possible to exchange data between remote computers, however, the point-to-point communication model was limited, as it did not allow for direct communication between any two arbitrary systems, a physical link was necessary. The technology was considered unsafe for strategic and military use because there were no alternative paths for the communication in case of an enemy attack. With limited exceptions, the earliest computers were connected directly to terminals used by individual users, such networks became known as local-area networks. Networking beyond this scope, known as wide-area networks, emerged during the 1950s, J. C. R. Licklider, Vice President at Bolt Beranek and Newman, Inc
28.
Mass media
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The mass media is a diversified collection of media technologies that reach a large audience via mass communication. The technologies through which communication takes place include a variety of outlets. Broadcast media transmit information electronically, via such media as film, radio, recorded music, digital media comprises both Internet and mobile mass communication. Internet media comprise such services as email, social sites, websites. Print media transmit information via physical objects, such as books, comics, magazines, newspapers, event organizing and public speaking can also be considered forms of mass media. The organizations that control these technologies, such as studios, publishing companies. In the late 20th century, mass media could be classified into eight mass media industries, books, the Internet, magazines, movies, newspapers, radio, recordings, and television. The explosion of digital technology in the late 20th and early 21st centuries made prominent the question. For example, it is whether to include cell phones, computer games. In the 2000s, a called the seven mass media became popular. For example, the Internet includes blogs, podcasts, web sites, the sixth and seventh media, Internet and mobile phones, are often referred to collectively as digital media, and the fourth and fifth, radio and TV, as broadcast media. Some argue that video games have developed into a mass form of media. While a telephone is a communication device, mass media communicates to a large group. In addition, the telephone has transformed into a phone which is equipped with Internet access. A question arises whether this makes cell phones a mass medium or simply a device used to access a mass medium. There is currently a system by which marketers and advertisers are able to tap into satellites and this transmission of mass advertising to millions of people is another form of mass communication. Video games may also be evolving into a mass medium, video games provide a common gaming experience to millions of users across the globe and convey the same messages and ideologies to all their users. Users sometimes share the experience with one another by playing online, excluding the Internet however, it is questionable whether players of video games are sharing a common experience when they play the game individually
29.
History of mobile phones
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The history of mobile phones, covers mobile communication devices which connect wirelessly to the public switched telephone network. While the transmission of speech by radio has a history, the first models that were wireless, mobile. The first such devices were barely portable compared to todays compact hand-held devices, before the devices that are now referred as mobile phones existed, there were some precursors. In 1908 a Professor Albert Jahnke and the Oakland Transcontinental Aerial Telephone and they were accused of fraud and the charge was then dropped, but they do not seem to have proceeded with production. Beginning in 1918 the German railroad system tested wireless telephony on military trains between Berlin and Zossen, in 1924, public trials started with telephone connection on trains between Berlin and Hamburg. In 1925, the company Zugtelephonie A. G, the portrayal of a Utopia of mobile phone in literature dates back to the year 1931. It is found in Erich Kästners childrens book The 35th of May, or Conrads Ride to the South Seas, hand-held radio transceivers have been available since the 1940s. Mobile telephones for automobiles became available from some companies in the 1940s. Early devices were bulky, consumed high power, and the network supported only a few simultaneous conversations, modern cellular networks allow automatic and pervasive use of mobile phones for voice and data communications. Shortly after, AT&T offered Mobile Telephone Service, a wide range of mostly incompatible mobile telephone services offered limited coverage area and only a few available channels in urban areas. One of the earliest fictional descriptions of a phone was the 1948 science fiction novel Space Cadet by Robert Heinlein. The protagonist, who has just traveled to Colorado from his home in Des Moines, receives a call from his father on a pocket telephone. Before going to space he decides to ship the telephone home since it was limited by its range to the neighborhood of an earth-side relay office. Ten years later, an essay by Arthur C. Clarke envisioned a personal transceiver, so small and he wrote, the time will come when we will be able to call a person anywhere on Earth merely by dialing a number. Such a device would also, in Clarkes vision, include means for global positioning so that no one need ever again be lost, later, in Profiles of the Future, he predicted the advent of such a device taking place in the mid-1980s. U. S. TV series Get Smart depicted spy gadgets with mobile telephones concealed in random objects, in the USSR, Leonid Kupriyanovich, an engineer from Moscow, in 1957-1961 developed and presented a number of experimental models of handheld mobile phones. The weight of one model, presented in 1961, was only 70 g, however, in the USSR the decision at first to develop the system of the automobile Altai phone was made. In 1965, Bulgarian company Radioelektronika presented on the Inforga-65 international exhibition in Moscow the mobile automatic phone combined with a base station, solutions of this phone were based on a system developed by Leonid Kupriyanovich
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Optical communication
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Optical communication, also known as optical telecommunication, is communication at a distance using light to carry information. It can be performed visually or by using electronic devices, the earliest basic forms of optical communication date back several millennia, while the earliest electrical device created to do so was the photophone, invented in 1880. When electronic equipment is not employed the receiver is a person visually observing and interpreting a signal, free-space optical communication has been deployed in space, while terrestrial forms are naturally limited by geography, weather and the availability of light. This article provides an introduction to different forms of optical communication. Visual techniques such as signals, beacon fires, hydraulic telegraphs, ship flags. Hydraulic telegraph semaphores date back to the 4th century BCE Greece, distress flares are still used by mariners in emergencies, while lighthouses and navigation lights are used to communicate navigation hazards. The heliograph uses a mirror to reflect sunlight to a distant observer, when a signaler tilts the mirror to reflect sunlight, the distant observer sees flashes of light that can be used to transmit a prearranged signaling code. Naval ships often use signal lamps and Morse code in a similar way, aircraft pilots often use visual approach slope indicator projected light systems to land safely, especially at night. Military aircraft landing on an aircraft carrier use a system to land correctly on a carrier deck. The coloured light system communicates the aircrafts height relative to a standard landing glideslope, as well, airport control towers still use Aldis lamps to transmit instructions to aircraft whose radios have failed. In the present day a variety of electronic systems optically transmit, free-space optical communications are also used every day in various applications. Information is encoded by the position of the elements, it is read when the shutter is in a fixed position. Semaphore lines were a precursor of the electrical telegraph and they were far faster than post riders for conveying a message over long distances, but far more expensive and less private than the electrical telegraph lines which would later replace them. Each relay station would require its complement of skilled operator-observers to convey messages back. His proposal was not put into practice during his lifetime and it was used for military and national communications until the 1850s. Many national services adopted signaling systems different from the Chappe system, for example, Britain and Sweden adopted systems of shuttered panels. In Spain, the engineer Agustín de Betancourt developed his own system which was adopted by that state and this system was considered by many experts in Europe better than Chappes, even in France. These systems were popular in the late 18th to early 19th century but could not compete with the electrical telegraph, and went completely out of service by 1880
31.
Semaphore line
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A semaphore telegraph is a system of conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the elements, it is read when the shutter is in a fixed position. The most widely used system was invented in 1792 in France by Claude Chappe and they were much faster than post riders for conveying a message over long distances, and also had cheaper long-term operating costs, once constructed. Semaphore lines were a precursor of the telegraph, which would replace them half a century later, and would also be cheaper, faster. The distance that an optical telegraph can bridge is limited by geography and weather, thus, in practical use and this also prevented the optical telegraph from crossing wide expanses of water, unless a convenient island could be used for a relay station. Modern derivatives of the system include flag semaphore and the heliograph. The word semaphore was coined in 1801 by the French inventor of the line itself. He composed it from the Greek elements σῆμα, and from φορός, Chappe also coined the word telegraph. The word semaphoric was first printed in English in 1808, The newly constructed Semaphoric telegraphs, semaphore telegraphs are also called optical telegraphs, shutter telegraph chains, Chappe telegraphs or Napoleonic semaphore. Optical telegraphy dates from ancient times, in the form of hydraulic telegraphs, torches, the system was never put into practice. One of the first experiments of optical signalling was carried out by the Anglo-Irish landowner and inventor and he placed a bet with his friend, the horse racing gambler Lord Marsh, that he could transmit knowledge of the outcome of the race in just one hour. Using a network of signalling sections erected on ground, the signal would be observed from one station to the next by means of a telescope. The signal itself consisted of a pointer that could be placed into eight possible positions in 45 degree increments. A series of two such signals gave a total 64 code elements and a third signal took it up to 512 and he only returned to his idea in 1795, after hearing of Chappes system. Le système Chappe was used for military and national communications until the 1850s, during 1790–1795, at the height of the French Revolution, France needed a swift and reliable communication system to thwart the war efforts of its enemies. France was surrounded by the forces of Britain, the Netherlands, Prussia, Austria, and Spain, the cities of Marseille and Lyon were in revolt, the only advantage France held was the lack of cooperation between the allied forces due to their inadequate lines of communication. On 2 March 1791 at 11am, they sent the message “si vous réussissez, the first means used a combination of black and white panels, clocks, telescopes, and codebooks to send their message. However, in the summer of 1792 Claude was appointed Ingénieur-Télégraphiste and it was used to carry dispatches for the war between France and Austria
32.
Pager
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A pager is a wireless telecommunications device that receives and displays alphanumeric messages and/or receives and announces voice messages. One-way pagers can only receive messages, while response pagers and two-way pagers can also acknowledge, reply to, Pagers operate as part of a paging system which includes one or more fixed transmitters, as well as a number of pagers carried by mobile users. These systems can range from a restaurant system with a single low-power transmitter, in the 2000s, the widespread availability of cellphones and smartphones has greatly diminished the pager industry. This resilience has led public safety agencies to adopt pagers over cellular, the first telephone pager system was patented in 1949 by Alfred J. Gross. One of the first practical paging services was launched in 1950 for physicians in the New York City area, physicians paid $12 per month for the service and carried a 200-gram pager that would receive phone messages within 40 kilometres of a single transmitter tower. The system was manufactured by the Reevesound Company and operated by Telanswerphone, in 1962 the Bell System—the U. S. telephone monopoly colloquially known as Ma Bell—presented its Bellboy radio paging system at the Seattle Worlds Fair. Bellboy was the first commercial system for personal paging and it also marked one of the first consumer applications of the transistor, for which three Bell Labs inventors received a Nobel Prize in Physics in 1956. Solid-state circuitry enabled the Bellboy pager, about the size of a small TV remote device, to fit into a pocket or purse. The Bellboy was a terminal that notified the user when someone was trying to call them, when the person received an audible signal on the pager, he found a telephone and called the service centre, which informed him of the callers message. The ReFLEX protocol was developed in the mid 1990s, another is a facility handling classified information, where various radio transmitter or data storage devices are excluded to ensure security. First responders in rural areas with inadequate cellular coverage are often issued pagers, volunteer firefighters, EMS paramedics, and rescue squad members usually carry pagers to alert them of emergency call outs for their department. These pagers receive a tone from a fire department radio frequency. Restaurant pagers are in use in the 2000s. Customers are given a portable receiver that usually vibrates, flashes, Pagers have been popular with birdwatchers in Britain and Ireland since 1991, with companies Rare Bird Alert and Birdnet Information offering news of rare birds sent to pagers that they sell. The U. S. paging industry generated $2.1 billion in revenue in 2008, in Canada,161,500 Canadians paid $18.5 million for pager service in 2013. Telus, one of the three major carriers, announced the end to its Canadian pager service as of March 31,2015. Many paging network operators now allow numeric and textual pages to be submitted to the paging networks via email and this can result in pager messages being delayed or lost. Older forms of message submission using the Telelocator Alphanumeric Protocol involve modem connections directly to a paging network, for this reason, older forms of message submission retain their usefulness for disseminating highly-important alerts to users such as emergency services personnel
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Photophone
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The photophone is a telecommunications device that allows transmission of speech on a beam of light. It was invented jointly by Alexander Graham Bell and his assistant Charles Sumner Tainter on February 19,1880, at Bells laboratory at 1325 L Street in Washington, both were later to become full associates in the Volta Laboratory Association, created and financed by Bell. On June 3,1880, Bells assistant transmitted a voice telephone message from the roof of the Franklin School to the window of Bells laboratory. Bell believed the photophone was his most important invention, the photophone was a precursor to the fiber-optic communication systems that achieved worldwide popular usage starting in the 1980s. The master patent for the photophone was issued in December 1880, in its initial form, the photophone receiver was also non-electronic. Bell found that many substances could be used as direct light-to-sound transducers, in its ultimate electronic form, the photophone receiver used a simple selenium cell at the focus of a parabolic mirror. The cells electrical resistance varied inversely with the light falling upon it, i. e. its resistance was higher when dimly lit, the selenium modulated the current flowing through the circuit, and the current was converted back into variations of air pressure—sound—by the earphone. Bell used the name for a while but it should not be confused with the later invention radiophone which used radio waves, in his experiments, Sabine used a meter to see the effects of light acting on selenium connected in a circuit to a battery. However Bell reasoned that by adding a telephone receiver to the circuit he would be able to hear what Sabine could only see. S. 1874 Transit of Venus Commission, for his new L Street laboratory in Washington, when the modulated light beam fell upon their selenium receiver Bell, on his headphones, was able to clearly hear Tainter singing Auld Lang Syne. In an April 1,1880 Washington, D. C. experiment, Bell, the receiver was a parabolic mirror with selenium cells at its focal point. The telephone itself was something of a novelty, and radio was decades away from commercialization. He wrote somewhat enthusiastically, Bell transferred the photophones intellectual property rights to the American Bell Telephone Company in May 1880, factors such as the weather and the lack of light inhibited the use of Bells invention. Not long after its invention laboratories within the Bell System continued to improve the photophone in the hope that it could supplement or replace expensive conventional telephone lines. Its earliest non-experimental use came with military communication systems during World War I and II, Bell pondered the photophones possible scientific use in the spectral analysis of artificial light sources, stars and sunspots. The German Siemens & Halske Company boosted the range by utilizing current-modulated carbon arc lamps which provided a useful range of approximately 8 kilometres. They produced units commercially for the German Navy, which were adapted to increase their range to 11 kilometres using voice-modulated ship searchlights. British Admiralty research during WWI resulted in the development of a vibrating mirror modulator in 1916, more sensitive molybdenite receiver cells, which also had greater sensitivity to infra-red radiation, replaced the older selenium cells in 1917
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History of radio
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The early history of radio is the history of technology that produce and use radio instruments that use radio waves. Within the timeline of radio, many people contributed theory and inventions in what became radio, Radio development began as wireless telegraphy. Later radio history increasingly involves matters of broadcasting, james Clerk Maxwell showed in theoretical and mathematical form in 1864 that electromagnetic waves could propagate through free space. In 1888 Heinrich Rudolf Hertz was able to conclusively prove transmitted airborne electromagnetic waves in an experiment confirming Maxwells theory of electromagnetism, over several years starting in 1894 the Italian inventor Guglielmo Marconi built the first complete, commercially successful wireless telegraphy system based on airborne Hertzian waves. Marconi demonstrated application of radio in military and marine communications and started a company for the development and propagation of radio communication services and equipment. In 1886–88 Heinrich Rudolf Hertz conducted a series of experiments that proved the existence of Maxwells electromagnetic waves, many individuals—inventors, engineers, developers and businessmen—constructed systems based on their own understanding of these and other phenomenon, some predating Maxwell and Hertzs discoveries. Thus wireless telegraphy and radio wave-based systems can be attributed to multiple inventors, development from a laboratory demonstration to a commercial entity spanned several decades and required the efforts of many practitioners. In 1878, David E. Hughes noticed that sparks could be heard in a telephone receiver when experimenting with his carbon microphone and he developed this carbon-based detector further and eventually could detect signals over a few hundred yards. He demonstrated his discovery to the Royal Society in 1880, but was told it was merely induction, thomas Edison came across the electromagnetic phenomenon while experimenting with a telegraph at Menlo Park. He noted an unexplained transmission effect while experimenting with a telegraph and he referred to this as etheric force in an announcement on November 28,1875. Elihu Thomson published his findings on Edisons new force, again attributing it to induction, Edison would go on the next year to take out U. S. Patent 465,971 on a system of wireless communication between ships based on electrostatic coupling using the water and elevated terminals. Although this was not a system the Marconi Company would purchase the rights in 1903 to protect them legally from lawsuits. Between 1886 and 1888 Heinrich Rudolf Hertz published the results of his experiments where he was able to transmit electromagnetic waves through the air, early on after their discovery, radio waves were referred to as Hertzian waves. Tesla, concluding that Hertz had not demonstrated airborne electromagnetic waves, went on to develop a system based on what he thought was the primary conductor, during the demonstration a radio signal was sent from the neighboring Clarendon Laboratory building, and received by apparatus in the lecture theater. Bose wrote in a Bengali essay, Adrisya Alok, The invisible light can pass through brick walls. Therefore, messages can be transmitted by means of it without the mediation of wires, Bose’s first scientific paper, On polarisation of electric rays by double-refracting crystals was communicated to the Asiatic Society of Bengal in May 1895. His second paper was communicated to the Royal Society of London by Lord Rayleigh in October 1895, in December 1895, the London journal The Electrician published Bose’s paper, On a new electro-polariscope
35.
Radiotelephone
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A radiotelephone is a communications system for transmission of speech over radio. Radiotelephone systems are not necessarily interconnected with the land line telephone network. Radiotelephony means transmission of sound by radio, in contrast to radiotelegraphy or video transmission, the word phone has a long precedent beginning with early US wireless voice systems. The term means voice as opposed to telegraph or Morse code and this would include systems fitting into the category of two-way radio or one-way voice broadcasts such as coastal maritime weather. The term is popular in the amateur radio community and in US Federal Communications Commission regulations. A standard landline telephone allows both users to talk and listen simultaneously, effectively there are two channels between the two end-to-end users of the system. It is, however, the most comfortable method of communication for users. The most common method of working for radiotelephones is half-duplex, operation, which one person to talk. If a single channel is used, both take turns to transmit on it. An eavesdropper would hear both sides of the conversation, dual-frequency working splits the communication into two separate channels, but only one is used to transmit at a time. The end users have the experience as single frequency simplex. The user presses a switch on the transmitter when they wish to talk—this is called the press-to-talk switch or PTT. It is usually fitted on the side of the microphone or other obvious position, users may use a special code-word such as over to signal that they have finished transmitting, or it may follow from the conversation. Radiotelephones may operate at any frequency where they are licensed to do so and they may use simple modulation schemes such as AM or FM, or more complex techniques such as digital coding, spread spectrum, and so on. Licensing terms for a band will usually specify the type of modulation to be used. For example, airband radiotelephones used for air to ground communication between pilots and controllers operates in the VHF band from 118.0 to 136.975 MHz, Radiotelephone receivers are usually designed to a very high standard, and are usually of the double-conversion superhet design. Multiple channels are provided using a frequency synthesizer. Receivers usually features a squelch circuit to cut off the output from the receiver when there is no transmission to listen to
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Flag semaphore
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Flag semaphore is the telegraphy system conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags, it is read when the flag is in a fixed position, semaphores were adopted and widely used in the maritime world in the 19th century. It is still used during underway replenishment at sea and is acceptable for emergency communication in daylight or, using lighted wands instead of flags, at night. The current flag semaphore system uses two short poles with flags, which a signalman holds in different positions to signal letters of the alphabet. The signalman holds one pole in each hand, and extends each arm in one of eight possible directions, except for in the rest position, the flags do not overlap. The flags are colored based on whether the signals are sent by sea or by land. At sea, the flags are colored red and yellow, while on land, they are white, flags are not required, their purpose is to make the characters more obvious. The following 30 semaphore characters are presented as they would appear when facing the signalman, letters can be signaled by first signaling J. The sender uses the Attention signal to request permission to begin a transmission, the receiver uses a Ready to receive signal not shown above to grant permission to begin the transmission. The receiver raises both flags vertical overhead and then drops them to the rest position, once only, to grant permission to send, the sender ends the transmission with the Ready to receive signal. The receiver can reply with the Attention signal, at this point, sender and receiver change places. The Japanese merchant marine and armed services have adapted the flag system to the Japanese language. The flags are specified as a white square for the left hand. It is the arm, holding the red flag, which moves as a pen would. As in telegraphy, the syllabary is the one used to write down the messages as they are received. Also, the Japanese system presents the number 0 by moving flags in a circle, and those from 1 through 9 using a sort of the dial system. Semaphore flags are sometimes used as means of communication in the mountains where oral or electronic communication is difficult to perform. Although they do not carry flags, the Royal Canadian Mounted Police officers have used hand semaphore in this manner, some surf-side rescue companies, such as the Ocean City Maryland Beach Patrol, use semaphore flags to communicate between lifeguards
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Smartphone
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A smartphone is a mobile phone with an advanced mobile operating system that combines features of a personal computer operating system with other features useful for mobile or handheld use. Smartphones can access the Internet and can run a variety of third-party software components and they typically have a color display with a graphical user interface that covers more than 76% of the front surface. In 1999, the Japanese firm NTT DoCoMo released the first smartphones to achieve mass adoption within a country, smartphones became widespread in the late 2000s. Most of those produced from 2012 onward have high-speed mobile broadband 4G LTE, motion sensors, in the third quarter of 2012, one billion smartphones were in use worldwide. Global smartphone sales surpassed the sales figures for regular cell phones in early 2013, devices that combined telephony and computing were first conceptualized by Nikola Tesla in 1909 and Theodore Paraskevakos in 1971 and patented in 1974, and were offered for sale beginning in 1993. Paraskevakos was the first to introduce the concepts of intelligence, data processing and they were installed at Peoples Telephone Company in Leesburg, Alabama and were demonstrated to several telephone companies. The original and historic working models are still in the possession of Paraskevakos, the first mobile phone to incorporate PDA features was a prototype developed by Frank Canova in 1992 while at IBM and demonstrated that year at the COMDEX computer industry trade show. It included PDA features and other mobile applications such as maps, stock reports. A refined version was marketed to consumers in 1994 by BellSouth under the name Simon Personal Communicator, the Simon was the first commercially available device that could be properly referred to as a smartphone, although it was not called that in 1994. The term smart phone appeared in print as early as 1995, in the mid-late 1990s, many mobile phone users carried a separate dedicated PDA device, running early versions of operating systems such as Palm OS, BlackBerry OS or Windows CE/Pocket PC. These operating systems would later evolve into mobile operating systems, in March 1996, Hewlett-Packard released the OmniGo 700LX, a modified HP 200LX palmtop PC that supported a Nokia 2110 phone with ROM-based software to support it. It had a 640×200 resolution CGA compatible four-shade gray-scale LCD screen and could be used to place and receive calls and it was also 100% DOS5.0 compatible, allowing it to run thousands of existing software titles, including early versions of Windows. In August 1996, Nokia released the Nokia 9000 Communicator, a cellular phone based on the Nokia 2110 with an integrated PDA based on the PEN/GEOS3.0 operating system from Geoworks. The two components were attached by a hinge in what known as a clamshell design, with the display above. The PDA provided e-mail, calendar, address book, calculator and notebook applications, text-based Web browsing, when closed, the device could be used as a digital cellular phone. In June 1999 Qualcomm released the pdQ Smartphone, a CDMA digital PCS Smartphone with an integrated Palm PDA, subsequent landmark devices included, The Ericsson R380 by Ericsson Mobile Communications. The first device marketed as a smartphone, it combined the functions of a phone and PDA. The Kyocera 6035 introduced by Palm, Inc, combining a PDA with a mobile phone, it operated on the Verizon network, and supported limited Web browsing
38.
Smoke signal
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The smoke signal is one of the oldest forms of long-distance communication. It is a form of communication used over long distance. In general smoke signals are used to transmit news, signal danger, in ancient China, soldiers stationed along the Great Wall would alert each other of impending enemy attack by signaling from tower to tower. In this way, they were able to transmit a message as far away as 750 kilometres in just a few hours, abuse of the smoke signal is known to have contributed to the fall of the Western Zhou Dynasty in the 8th century BCE. King You of Zhou had a habit of fooling his warlords with false warning beacons in order to amuse Bao Si, when an actual rebellion occurred, no one came to the aid of the king. Polybius, a Greek historian, devised a complex system of alphabetical smoke signals around 150 BCE. It enabled messages to be signaled by holding sets of torches in pairs. This idea, known as the Polybius square, also lends itself to cryptography and steganography and this cryptographic concept has been used with Japanese Hiragana and the Germans in the later years of the First World War. The North American indigenous peoples also communicated via smoke signal, each tribe had its own signaling system and understanding. A signaler started a fire on an elevation typically using damp grass, the grass would be taken off as it dried and another bundle would be placed on the fire. Reputedly the location of the smoke along the incline conveyed a meaning, if it came from halfway up the hill, this would signify all was well, but from the top of the hill it would signify danger. Smoke signals remain in use today, in Rome, the College of Cardinals uses smoke signals to indicate the selection of a new Pope during a papal conclave. Eligible cardinals conduct a ballot until someone receives a vote of two-thirds plus one. The ballots are burned after each vote, black smoke indicates a failed ballot, while white smoke means a new Pope has been elected. Smoke signals may also refer to smoke-producing devices used to send distress signals, yámanas used fire to send messages by smoke signals, for instance if a whale drifted ashore. The large amount of meat required notification of many people, so that it would not decay and they might also have used smoke signals on other occasions, thus it is possible that Magellan saw such fires but he may have seen the smoke or lights of natural phenomena. Noon Gun time signalling was used to set marine chronometers in Table Bay, aboriginal Australians in the Western Desert would send up smoke to notify others of their presence, particularly when entering lands which were not their own. Putting up a smoke would often result in individuals or groups replying with their own signals
39.
Telautograph
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It was the first such device to transmit drawings to a stationary sheet of paper, previous inventions in Europe had used rotating drums to make such transmissions. The telautographs invention is attributed to Elisha Gray, who patented it on July 31,1888, grays patent stated that the telautograph would allow one to transmit his own handwriting to a distant point over a two-wire circuit. It was the first facsimile machine in which the stylus was controlled by horizontal and vertical bars, the telautograph was first publicly exhibited at the 1893 Worlds Columbian Exposition held in Chicago. What you write in Chicago is instantly reproduced here in fac-simile and you may write in any language, use a code or cipher, no matter, a fac-simile is produced here. If you want to draw a picture it is the same, the artist of your newspaper can, by this device, telegraph his pictures of a railway wreck or other occurrences just as a reporter telegraphs his description in words. By the end of the 19th century, the telautograph was modified by Foster Ritchie, calling it the telewriter, Ritchies version of the telautograph could be operated using a telephone line for simultaneous copying and speaking. Teleautograph systems were installed in a number of railroad stations to relay hand-written reports of train movements from the interlocking tower to various parts of the station. The teleautograph network in Grand Central Terminal included a display in the main concourse into the 1960s. A Telautograph was used in 1911 to warn workers on the 10th floor about the Triangle Shirtwaist Factory fire that had broken out two floors below. An example of a Telautograph machine writing script can be seen in the 1956 movie Earth vs the Flying Saucers as the device for the mechanical translator. Telautograph Corporation changed its name several times, in 1971, it was acquired by Arden/Mayfair. In 1993, Danka Industries purchased the company and renamed it Danka/Omnifax, in 1999, Xerox corporation purchased the company and called it the Omnifax division, which has since been absorbed by the corporation. Archive of Xerox Omnifax Division website, the successor to Telautograph Corporation, Telautograph historical description Patent images in TIFF format U. S. Patent 0,386,814 Art of Telegraphy, issued July 1888 U. S, Patent 0,386,815 Telautograph, issued July 1888 U. S. Patent 0,461, 470Telautograph, issued October 1891 U. S, Patent 0,461,472 Art of and Apparatus for Telautographic Communication, issued October 1891 U. S. Patent 0,491,347 Telautograph, issued February 1893 U. S, Patent 0,494,562 Telautograph, issued April 1893
40.
Telegraphy
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Telegraphy is the long-distance transmission of textual or symbolic messages without the physical exchange of an object bearing the message. Thus semaphore is a method of telegraphy, whereas pigeon post is not, telegraphy requires that the method used for encoding the message be known to both sender and receiver. Such methods are designed according to the limits of the medium used. The use of signals, beacons, reflected light signals. In the 19th century, the harnessing of electricity led to the invention of electrical telegraphy, the advent of radio in the early 20th century brought about radiotelegraphy and other forms of wireless telegraphy. The word telegraph was first coined by the French inventor of the Semaphore line, Claude Chappe, a telegraph is a device for transmitting and receiving messages over long distances, i. e. for telegraphy. The word telegraph alone now generally refers to an electrical telegraph, Wireless telegraphy is also known as CW, for continuous wave, as opposed to the earlier radio technique of using a spark gap. Contrary to the definition used by Chappe, Morse argued that the term telegraph can strictly be applied only to systems that transmit. This is to be distinguished from semaphore, which transmits messages. Smoke signals, for instance, are to be considered semaphore, according to Morse, telegraph dates only from 1832 when Pavel Schilling invented one of the earliest electrical telegraphs. A telegraph message sent by a telegraph operator or telegrapher using Morse code was known as a telegram. A cablegram was a sent by a submarine telegraph cable. Later, a Telex was a sent by a Telex network. A wire picture or wire photo was a picture that was sent from a remote location by a facsimile telegraph. A diplomatic telegram, also known as a cable, is the term given to a confidential communication between a diplomatic mission and the foreign ministry of its parent country. These continue to be called telegrams or cables regardless of the used for transmission. Commercial electrical telegraphs were introduced from 1837, the first telegraphs came in the form of optical telegraph, including the use of smoke signals, beacons, or reflected light, which have existed since ancient times. Early proposals for a telegraph system were made to the Royal Society by Robert Hooke in 1684 and were first implemented on an experimental level by Sir Richard Lovell Edgeworth in 1767
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Teleprinter
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A teleprinter is an electromechanical typewriter that can be used to send and receive typed messages from point to point and point-to-multipoint over various types of communications channels. They were adapted to provide an interface to early mainframe computers and minicomputers, sending typed data to the computer. Some models could also be used to create punched tape for data storage, teleprinters could use a variety of different communication media. These included a pair of wires, dedicated non-switched telephone circuits, switched networks that operated similarly to the public telephone network. A teleprinter attached to a modem could also communicate through standard switched public telephone lines and this latter configuration was often used to connect teleprinters to remote computers, particularly in time-sharing environments. Teleprinters have largely replaced by fully electronic computer terminals which usually use a computer monitor instead of a printer. Teleprinters were invented in order to send and receive messages without the need for operators trained in the use of Morse code, a system of two teleprinters, with one operator trained to use a typewriter, replaced two trained Morse code operators. The teleprinter system improved message speed and delivery time, making it possible for messages to be flashed across a country with little manual intervention, in 1835 Samuel Morse devised a recording telegraph. In 1841 Alexander Bain devised a printing telegraph, by 1846, the Morse telegraph service was operational between Washington, D. C. and New York. Royal Earl House patented his printing telegraph that same year and he linked two 28-key piano-style keyboards by wire. Each piano key represented a letter of the alphabet and when pressed caused the letter to print at the receiving end. A shift key gave each main key two optional values, a 56-character typewheel at the sending end was synchronised to coincide with a similar wheel at the receiving end. It was thus an example of a data transmission system. Houses equipment could transmit around 40 instantly readable words per minute, the printer could copy and print out up to 2,000 words per hour. This invention was first put in operation and exhibited at the Mechanics Institute in New York in 1844, landline teleprinter operations began in 1849 when a circuit was put in service between Philadelphia and New York City. In 1855, David Edward Hughes introduced a machine built on the work of Royal Earl House. Émile Baudot designed a system using a five unit code in 1874, the Baudot system was adopted in France in 1877, and later extensively in France. During 1901 Baudots code was modified by Donald Murray, prompted by his development of a typewriter-like keyboard
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History of the telephone
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This history of the telephone chronicles the development of the electrical telephone, and includes a brief review of its predecessors. Before the invention of electromagnetic telephones, mechanical acoustic devices existed for transmitting speech, the earliest mechanical telephones were based on sound transmission through pipes or other physical media. The acoustic tin can telephone, or lovers phone, has known for centuries. It connects two diaphragms with a string or wire, which transmits sound by mechanical vibrations from one to the other along the wire. The classic example is the toy made by connecting the bottoms of two paper cups, metal cans, or plastic bottles with tautly held string. Among the earliest known experiments were conducted by the British physicist. An acoustic string phone made in 1667 is attributed to him, for a short period of time, acoustic telephones were marketed commercially as a niche competitor to the electrical telephone. When Alexander Graham Bells telephone patent expired and many new telephone manufacturers began competing and their maximum range was very limited. An example of one company was the Pulsion Telephone Supply Company created by Lemuel Mellett in Massachusetts. Additionally, speaking tubes have long been common, especially within buildings and aboard ships, the telephone emerged from the making and successive improvements of the electrical telegraph. In 1804, Spanish polymath and scientist Francisco Salva Campillo constructed an electrochemical telegraph, the first working telegraph was built by the English inventor Francis Ronalds in 1816 and used static electricity. An electromagnetic telegraph was created by Baron Schilling in 1832, carl Friedrich Gauss and Wilhelm Weber built another electromagnetic telegraph in 1833 in Göttingen. The electrical telegraph was first commercialised by Sir William Fothergill Cooke and it ran for 13 mi from Paddington station to West Drayton and came into operation on April 9,1839. Another electrical telegraph was developed and patented in the United States in 1837 by Samuel Morse. His assistant, Alfred Vail, developed the Morse code signaling alphabet with Morse, americas first telegram was sent by Morse on January 6,1838, across 2 miles of wiring. Credit for the invention of the telephone is frequently disputed. Charles Bourseul, Innocenzo Manzetti, Antonio Meucci, Johann Philipp Reis, Alexander Graham Bell, the Bell and Edison patents, however, were commercially decisive, because they dominated telephone technology and were upheld by court decisions in the United States. The modern telephone is the result of work of many people, Alexander Graham Bell was, however, the first to patent the telephone, as an apparatus for transmitting vocal or other sounds telegraphically
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The Telephone Cases
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The Telephone Cases were a series of U. S. Those telephone patents were relied on by the American Bell Telephone Company, the objector in the notable Supreme Court case was initially the Western Union telegraph company, which was at the time a far larger and better financed competitor than American Bell Telephone. Had Western Union succeeded it would have destroyed the Bell Telephone Company. The U. S. Supreme Court came within one vote of overturning the Bell patent, I had been experimenting in that direction. I don’t remember of getting at it by accident either, I don’t remember of anyone talking to me of it. In this case the court affirmed several other court cases. V American Bell Tel. Co.15 Fed, Rep.604, Molecular Te. Co. et al. V American Bell Tel. Co.32 Fed, Rep 214, Peoples Tel. Co. et al. V American Bell Tel. Co.22 Fed, well reversing American Bell Tel Co. et al. Co et al.32 Fed Rep.214, bell’s second fundamental patent expired on January 30,1894, at which time the gates were then opened to independent telephone companies to compete with the Bell System. The Courts decision in the Telephone Cases is notable for the size of the opinions delivered, together, lawyers, Patents, and the Judgments of History, Technology and Culture, Vol.51, No. 4, October 2010, pp. 854–878, DOI,10. 1353/tech.2010.0038. Volume 126, Supreme Court Judgment 126 U. S.1 Dolbear v. American Bell etc at Open Jurist Volume 126, Supreme Court Judgment 126 U. S.1 Dolbear v. American Bell etc at Justia Legat, reproducing sounds on extra galvanic way. Quote, The Edison National Historical Park archives has seven bound volumes, four of these volumes contain the record of a group of interferences entitled Cases A through L and Case No.1. The disputant parties were Thomas Edison, Alexander Graham Bell, Elisha Gray, A. E. Dolbear, J. W. McDonough, richmond, William L. Voelker, J. H. Irwin, and Francis Blake, Jr. Although Edisons preliminary statements were filed in September 1878, testimony was not taken until 1880 and this record was printed in 1881. The second volume contains Edisons exhibits, including photo-lithographs of laboratory drawings, patents and patent applications, many of the documents in this numbered series were not selected as exhibits, they remain in the archives at the Edison National Historical Park
