1.
Communication
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Communication is the act of conveying intended meanings from one entity or group to another through the use of mutually understood signs and semiotic rules. The main steps inherent to all communication are, The forming of communicative motivation or reason, transmission of the encoded message as a sequence of signals using a specific channel or medium. Noise sources such as forces and in some cases human activity begin influencing the quality of signals propagating from the sender to one or more receivers. Reception of signals and reassemblying of the message from a sequence of received signals. Decoding of the encoded message. Interpretation and making sense of the original message. The channel of communication can be visual, auditory, tactile and haptic, olfactory, electromagnetic, human communication is unique for its extensive use of abstract language. Development of civilization has been linked with progress in telecommunication. Nonverbal communication describes the process of conveying information in the form of non-linguistic representations, examples of nonverbal communication include haptic communication, chronemic communication, gestures, body language, facial expressions, eye contact, and how one dresses. Nonverbal communication also relates to intent of a message, examples of intent are voluntary, intentional movements like shaking a hand or winking, as well as involuntary, such as sweating. Speech also contains nonverbal elements known as paralanguage, e. g. rhythm, intonation, tempo and it affects communication most at the subconscious level and establishes trust. Likewise, written texts include nonverbal elements such as handwriting style, spatial arrangement of words, Nonverbal communication demonstrates one of Wazlawicks laws, you cannot not communicate. Once proximity has formed awareness, living creatures begin interpreting any signals received, Nonverbal cues are heavily relied on to express communication and to interpret others’ communication and can replace or substitute verbal messages. There are several reasons as to why non-verbal communication plays a role in communication. Written communication can also have non-verbal attributes, e-mails and web chats allow individual’s the option to change text font colours, stationary, emoticons, and capitalization in order to capture non-verbal cues into a verbal medium. Many different non-verbal channels are engaged at the time in communication acts. “Non-verbal behaviours may form a language system. ”Smiling, crying, pointing, caressing. Such non-verbal signals allow the most basic form of communication when verbal communication is not effective due to language barriers, Verbal communication is the spoken or written conveyance of a message
2.
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
3.
AT&T Corporation
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Founded in 1885 as the original American Telephone and Telegraph Company, it was at times the worlds largest telephone company, the worlds largest cable television operator, and a regulated monopoly. At its peak in the 1950s and 1960s, it employed one million people, in 2005, AT&T was purchased by Baby Bell and former subsidiary SBC Communications for more than $16 billion. SBC then changed its name to AT&T Inc, AT&T started with Bell Patent Association, a legal entity established in 1874 to protect the patent rights of Alexander Graham Bell after he invented the telephone system. Originally a verbal agreement, it was formalized in writing in 1875 as Bell Telephone Company, in 1880 the management of American Bell had created what would become AT&T Long Lines. The project was the first of its kind to create a nationwide long-distance network with a commercially viable cost-structure, the project was formally incorporated in New York State as a separate company named American Telephone and Telegraph Company on March 3,1885. With this assets transfer, AT&T became the parent of both American Bell and the Bell System. AT&T was involved mainly in the business and, although it was a partner with RCA, was reluctant to see radio grow because such growth might diminish the demand for wired services. It established station WEAF in New York as what was termed a toll station, AT&T could provide no programming, but anyone who wished to broadcast a message could pay a toll to AT&T and then air the message publicly. The original studio was the size of a telephone booth, the idea, however, did not take hold, because people would pay to broadcast messages only if they were sure that someone was listening. As a result, WEAF began broadcasting entertainment material, drawing amateur talent found among its employees, throughout most of the 20th century, AT&T held a monopoly on phone service in the United States and Canada through a network of companies called the Bell System. At this time, the company was nicknamed Ma Bell, on April 30,1907, Theodore Newton Vail became President of AT&T. Vail believed in the superiority of one system and AT&T adopted the slogan One Policy, One System. This would be the philosophy for the next 70 years. Under Vail, AT&T began buying up many of the telephone companies including Western Union telegraph. Anxious to avoid action from government antitrust suits, AT&T and the government entered into an agreement known as the Kingsbury Commitment. These actions brought unwanted attention from antitrust regulators, in the Kingsbury Commitment, AT&T and the government reached an agreement that allowed AT&T to continue operating as a monopoly. While AT&T periodically faced scrutiny from regulators, this state of affairs continued until the breakup in 1984. The United States Justice Department opened the case United States v. AT&T in 1974 and this was prompted by suspicion that AT&T was using monopoly profits from its Western Electric subsidiary to subsidize the cost of its network, a violation of anti-trust law
4.
Western Electric
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Western Electric Company was an American electrical engineering and manufacturing company that served as the primary supplier to AT&T from 1881 to 1996. The company was responsible for technological innovations and seminal developments in industrial management. It also served as the agent for the member companies of the Bell System. In 1856, George Shawk purchased an engineering business in Cleveland. On December 31,1869, he partners with Enos M. Barton and, later the same year. In 1872 Barton, and Gray moved the business to Clinton Street, Chicago, Illinois, in 1875, Gray sold his interests to Western Union, including the caveat that he had filed against Alexander Graham Bells patent application for the telephone. Western Electric was the first company to join in a Japanese joint venture with foreign capital, in 1899, it invested in a 54% share of the Nippon Electric Company, Ltd. Western Electrics representative in Japan was Walter Tenney Carleton, in 1901, Western Electric secretly purchased a controlling interest in a principal competitor, the Kellogg Switchboard & Supply Company, but was later forced by a lawsuit to sell. On July 24,1915, employees of the Hawthorne Works boarded the SS Eastland in downtown Chicago for a company picnic, the ship rolled over at the dock and over 800 people died. In 1920, Alice Heacock Seidel was the first of Western Electrics female employees to be given permission to stay on after she had married and this set a precedent in the company, which previously had not allowed married women in their employ. Miss Heacock had worked for Western Electric for sixteen years before her marriage, if the women at the top were permitted to remain after marriage then all women would expect the same privilege. How far and how fast the policy was expanded is shown by the fact that a few years later women were given maternity leaves with no loss of time on their service records. In 1925, ITT purchased the Bell Telephone Manufacturing Company of Brussels, Belgium, the company manufactured rotary system switching equipment under the Western Electric brand. Early on, Western Electric also managed an electrical equipment distribution business, Bell Telephone Laboratories was half-owned by Western Electric, the other half belonging to AT&T. Western Electric used various logos during its existence, starting in 1914 it used an image of AT&Ts statue Spirit of Communication. In 1915, Western Electric Manufacturing was incorporated in New York, New York, as an owned subsidiary of AT&T, under the name Western Electric Company. AT&T and Bell System companies were rumored to employ small armies of inspectors to check household line voltage levels to determine if non-leased phones were in use by consumers. Western Electric telephones were owned not by end customers but by the local Bell System telephone companies—all of which were subsidiaries of AT&T, each phone was leased from the phone company on a monthly basis by customers who generally paid for their phone as part of the recurring lease fees
5.
Teletype Corporation
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Because of the nature of its business, as stated in the corporate charter, Teletype Corporation was allowed a unique mode of operation within Western Electric. It was organized as an entity, and contained all the elements necessary for a separate corporation. Teletypes charter permitted the sale of equipment to customers outside the AT&T Bell System, the primary customer outside of the Bell System was the United States Government. The Teletype Corporation continued in this manner until January 8,1982, the date of settlement of United States v. AT&T, at that time, Western Electric was fully absorbed into AT&T as AT&T Technologies, and the Teletype Corporation became AT&T Teletype. The last vestiges of what had been the Teletype Corporation ceased in 1990, one of the three Teletype manufacturing buildings in Skokie remains in use as a parking garage for a shopping center. Every other floor of the building has been removed, the other two buildings were demolished. The Teletype Corporation had its roots in the Morkrum Company, in 1902, electrical engineer Frank Pearne approached Joy Morton, head of Morton Salt, seeking a sponsor for Pearnes research into the practicalities of developing a printing telegraph system. Krum was interested in helping Pearne, so space was set up in a laboratory in the attic of Western Cold Storage, Frank Pearne lost interest in the project after a year, and left to get involved in teaching. Krum was prepared to continue Pearne’s work, and in August 1903 a patent was filed for a page printer. In 1904, Krum filed a patent for a type wheel printing telegraph machine which was issued in August 1907, in 1906, the Morkrum Company was formed, with the company name combining the Morton and Krum names and reflecting the financial assistance provided by Joy Morton. This is the time when Charles Krums son, Howard Krum and it was Howard who developed and patented the start-stop synchronizing method for code telegraph systems, which made possible the practical teleprinter. In 1908, a working teleprinter was produced, called the Morkrum Printing Telegraph, in 1925, the Morkrum Company and the Kleinschmidt Electric Company merged to form the Morkrum-Kleinschmidt Company. In December 1928, the changed its name to the less cumbersome Teletype Corporation. In 1930, the Teletype Corporation was purchased by the American Telephone and Telegraph Company for $30,000,000 in stock, while other principals in the Teletype Corporation retired, Howard Krum stayed on as a consultant. Morkrum Printing Telegraph – This was the first mechanically successful teleprinter, a Blue Code Version was used in 1910 as a part of the first commercial teleprinter circuit that ran on Postal Telegraph Company lines between Boston and New York City. In 1914, a Green Code Version was installed using Western Union Telegraph Company lines for the Associated Press and was used to distribute news to competing newspapers in New York City. The Model 11 was a Tape Printer which used gummed paper tape that could be pasted onto a telegram blank and this was the first teleprinter to successfully operate from an airplane. Morkrum Model GPE Perforator – The Morkrum Company Model GPE Green Code Perforator was designed about 1913 and this equipment continued to be produced for the next 50 years
6.
Skokie, Illinois
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Skokie is a village in Cook County, Illinois, United States. Its name comes from a Potawatomi word for marsh, a Chicago suburb, for many years Skokie promoted itself as The Worlds Largest Village. Its population, according to the 2010 census, was 64,784, Skokie was originally a German-Luxembourger farming community, but was later settled by a sizeable Jewish population, especially after World War II. At its peak in the mid-1960s, 58% of the population was Jewish, in recent years, several synagogues and Jewish schools have closed. However, Skokie still has a very large Jewish population and it is home to the Illinois Holocaust Museum and Education Center, which opened in northwest Skokie in 2009. Skokie has received national attention twice for court cases decided by the United States Supreme Court, in the mid-1970s, it was at the center of a case concerning the First Amendment right to assemble and the National Socialist Party of America, a neo-Nazi group. In 2001, although Skokie was not a party to the case. According to the 2010 census, Skokie has an area of 10.06 square miles. The east-west streets continue Evanstons street names, but with Chicago grid values, such that, Evanstons Dempster Street is 8800 north, in 1888, the community was incorporated as Niles Centre. About 1910, the spelling was Americanized to Niles Center, however, the name caused postal confusion with the neighboring village of Niles. A village-renaming campaign began in the 1930s, in a referendum on November 15,1940, residents chose the Indian name Skokie over the name Devonshire. During the real boom of the 1920s, large parcels were subdivided, many two- and three-flat apartment buildings were built. Large-scale development ended as a result of the Great Crash of 1929 and it was not until the 1940s and the 1950s, when parents of the baby boom generation moved their families out of Chicago, that Skokies housing development began again. Consequently, the village developed commercially, an example being the Old Orchard Shopping Center, peter Catholic Cemetery, a block north of Oakton Avenue in the town. The first African-American family to move to Skokie arrived in 1961, the name of the town was changed from Niles Center to Skokie by referendum in 1940. Maps long named the Skokie marsh as Chewab Skokie, a derivation from Kitchi-wap choku. Virgil Vogels Indian Place Names in Illinois records the name Skokie as deriving directly from skoutay or scoti, the reference is to the fact that marshy grasslands, such as occurred in the Skokie region, were burned by the Indians to flush out the game. Porter supported the name Skokie in the referendum when he returned to America, twice in its history, Skokie has been the focal point of cases before the United States Supreme Court
7.
Bell System
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On December 31,1983, the system was broken up into independent companies by a U. S. Justice Department mandate. Ma Bell is also used to refer to the female voices behind recordings for the Bell System, Mary Moore, Jane Barbe. In 1877, the American Bell Telephone Company, named after Alexander Graham Bell, opened the first telephone exchange in New Haven, within a few years local exchange companies were established in every major city in the United States. In 1899, American Telephone & Telegraph acquired the assets of its parent, originally American Bell had created AT&T to provide long-distance calls between New York and Chicago and beyond. AT&T became the parent of American Bell, and thus the head of the Bell System, because regulatory and tax rules were leaner in New York than in Boston, after 1934, AT&T was regulated by the Federal Communication Commission. Receiving a U. S. patent for the invention of the telephone on March 7,1876, Alexander Graham Bell formed the Bell Telephone Company in 1877, on April 30,1907, Theodore Newton Vail returned as President of AT&T. Vail believed in the superiority of one system and AT&T adopted the slogan One Policy, One System. This would be the philosophy for the next 70 years. Under Vail, AT&T began buying up many of the telephone companies including Western Union telegraph. Anxious to avoid action from government antitrust suits, AT&T entered into an agreement known as the Kingsbury Commitment with the federal government. S. The Bell trademark pictured here was used from 1921 through 1939 by both the AT&T corporation and the regional operating corporations to co-brand themselves under a single Bell System trademark, the regional operating corporations name was placed where name of associated company appears in this template version of the trademark. Bell system telephones and related equipment were made by Western Electric, member telephone companies paid a fixed fraction of their revenues as a license fee to Bell Labs. As a result of this monopoly, by 1940 the Bell System effectively owned most telephone service in the United States, from local. This allowed Bell to prohibit their customers from connecting phones not made or sold by Bell to the system without paying fees, Northern Electric was spun off in 1956 by Western Electric, but AT&T did not spin off Bell Canada until 1975. The Bell Systems Caribbean regional operating companies were sold to the ITT Corporation, before 1956, the Bell Systems reach was truly gargantuan. The 1984 Bell System divestiture brought an end to the branded as the Bell System. The suit was settled on January 8,1982, superseding the former restrictions that AT&T and the DOJ had agreed upon in 1956. Currently, the word mark Bell, the logo, and other related trademarks, are held by each of the remaining Bell companies, namely AT&T, Verizon, CenturyLink, and Cincinnati Bell
8.
Joy Morton
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Joy Sterling Morton was an American businessman and entrepreneur best known for founding Morton Salt and establishing the Morton Arboretum in Lisle, Illinois. He was born on September 27,1855 in Nebraska City and his mother, Caroline Joy, was an accomplished artist, musician, and gardener. His father, Julius Sterling Morton, a newspaperman and a leader in Nebraska territorial, J. Sterling Morton served as United States Secretary of Agriculture in the second administration of President Grover Cleveland. In 1880, Morton married Carrie Jane Lake, the daughter of Nebraska Supreme Court Judge George Lake, two years after Joy Morton’s first wife died in 1915, he married Margaret Gray, who became a local leader in health care. At 15, Morton began to manage the farm and estate. He also took a job at the local bank, at age 18, he fell ill with spinal meningitis. Needing physical exercise and an environment for full recovery, he farmed his own land for two years. Later, he worked for railroads in Omaha, Nebraska, and Aurora, Illinois, by 1886 he owned the firm, naming it Joy Morton and Company, and branched out into the distribution and processing of agricultural products in Nebraska and Illinois. In 1910 he incorporated his salt firm as the Morton Salt Company and he remained the companys president until 1930 when Daniel Peterkin, Sr. became president while he served as chairman of the board until his death in 1934. He died on May 9,1934 in Lisle, Illinois, among Morton’s brands are Morton Salt and Argo Starch. Morton also supported the development of the teleprinter and formed the Morkrum company with the inventor Howard Krum, the company was later renamed to Morkrum-Kleinschmidt, then to Teletype Corporation. It was sold to American Telephone & Telegraph Company in 1930 for $30,000,000, Morton took an active interest in the future of Chicago, chairing the Chicago Commercial Club’s railway terminal committee for Daniel Burnhams and Edward Bennett’s 1909 Plan of Chicago. Morton also served on the Chicago Plan Commission for 25 years and was an advocate of inland waterway transportation. His advocacy of air rights in Chicago helped make possible the construction of buildings above railway lines, throughout his life, Morton believed that inland waterways were essential to the development of commerce and to the growth of cities. In 1922, Morton established the Morton Arboretum on 178 acres of adjacent to his estate in Lisle. Today, the Morton Arboretum has grown to 1,700 acres, as Morton began to define the direction his arboretum should take, he sought the advice of Charles Sprague Sargent, the director of Harvard’s Arnold Arboretum. After his fathers death, he hired the architect Jarvis Hunt to redesign and enlarge Arbor Lodge into a 52-room mansion and used it as his familys summer home. After he began his own arboretum, Morton honored his father by giving Arbor Lodge, today Arbor Lodge is officially known as Arbor Lodge State Historical Park and Arboretum
9.
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
10.
Underwood Typewriter Company
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The Underwood Typewriter Company was a manufacturer of typewriters headquartered in New York City, New York. Underwood produced what is considered the first widely successful, modern typewriter, by 1939, Underwood had produced five million machines. From 1874, the Underwood family made typewriter ribbon and carbon paper, when Remington decided to start producing ribbons themselves, the Underwoods opted to manufacture typewriters. The original Underwood typewriter was invented by German-American Franz Xaver Wagner, Underwood supported Wagner and bought the company, recognising the importance of the machine. 2s, made between 1896 and 1900, had Wagner Typewriter Co. printed on the back, the Underwood No.5 launched in 1900 has been described as the first truly modern typewriter. Two million had sold by the early 1920s, and its sales “were equal in quantity to all of the other firms in the typewriter industry combined”. When the company was in its heyday as the worlds largest typewriter manufacturer, its factory at Hartford, Underwood started adding addition and subtraction devices to their typewriters in about 1910. Philip Dakin Wagoner was appointed president of the Elliott-Fisher Company after World War I, Elliott-Fisher became the parent of the Underwood Typewriter Company and the Sundstrand Corporation. In 1927 Wagoner reorganized the company into Underwood-Elliott-Fisher, which became the Underwood Corporation. The reorganization was completed in December 1927, John Thomas Underwood was elected chairman and Wagoner president of Underwood Elliott-Fisher. In the years before World War II, Underwood built the worlds largest type writer in an attempt to promote itself, the typewriter was on display at Garden Pier in Atlantic City, New Jersey for several years and attracted large crowds. Often, Underwood would have a woman sitting on each of the large keys. The enormous typewriter was scrapped for metal when the war started, during World War II Underwood produced M1 carbines. In 1945 Wagoner was elected chairman of the board of Underwood, the Underwood name last appeared on Olivetti portable typewriters produced in Spain in the 80s. The Between the Lions episode Clickety Clack, Clickety Clack used an Underwood typewriter, in the 1991 Coen brothers film Barton Fink, John Turturros character Barton uses an Underwood typewriter in response to Jack Warners comment that screenwriters are Schmucks with Underwoods. Warner In the 2000 film He Died with a Felafel in His Hand directed by Richard Lowenstein, in the 2002 Steven Spielberg film Catch Me If You Can, Carl Hanratty shows Frank Abagnale a forged check, which he says was made with a stencil machine and an Underwood. An Underwood typewriter is featured on Fionn Regans 2006 album The End of History, an Underwood typewriter is used by the main character in the 2001 musical film Moulin Rouge. William Faulkner, F. Scott Fitzgerald, Ernest Hemingway, Jack Kerouac used an Underwood Portable Typewriter when he wrote On the Road
11.
Baudot code
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The Baudot code, invented by Émile Baudot, is a character set predating EBCDIC and ASCII. It was the predecessor to the International Telegraph Alphabet No,2, the teleprinter code in use until the advent of ASCII. Each character in the alphabet is represented by a series of bits, the symbol rate measurement is known as baud, and is derived from the same name. Technically, five-bit codes began in the 16th century, when Francis Bacon developed the now called Bacons cipher. However, this cipher is not a cipher and as such is not readily suitable for telecommunications. Baudot invented his original code in 1870 and patented it in 1874 and it was a 5-bit code, with equal on and off intervals, which allowed telegraph transmission of the Roman alphabet and punctuation and control signals. It was based on an earlier code developed by Carl Friedrich Gauss and it was a Gray code, nonetheless, the code by itself was not patented because French patent law does not allow concepts to be patented. Baudots original code was adapted to be sent from a manual keyboard, the code was entered on a keyboard which had just five piano type keys, operated with two fingers of the left hand and three fingers of the right hand. Operators had to maintain a rhythm, and the usual speed of operation was 30 words per minute. The table on the shows the allocation of the Baudot code which was employed in the British Post Office for continental. It will be observed that a number of characters in the code are replaced by fractionals in the inland code. Code elements 1,2 and 3 are transmitted by keys 1,2 and 3, code elements 4 and 5 are transmitted by keys 4 and 5, and these are operated by the first two fingers of the left hand. Baudots code became known as International Telegraph Alphabet No,1, and is no longer used. In 1901, Baudots code was modified by Donald Murray, prompted by his development of a typewriter-like keyboard. The Murray system employed an intermediate step, a keyboard perforator, which allowed an operator to punch a tape. At the receiving end of the line, a mechanism would print on a paper tape. For example, the letters are E and T. The ten two-hole letters are AOINSHRDLZ, very similar to the Etaoin shrdlu order used in Linotype machines, ten more letters have three holes, and the four-hole letters are VXKQ
12.
Telex
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The telex network is a switched network of teleprinters similar to a telephone network, for the purposes of sending text-based messages. The term refers to the network, not the teleprinters, point-to-point teleprinter systems had been in use long before telex exchanges were formed starting in the 1930s. Teleprinters evolved from systems, and like the telegraph they used the presence or absence of a pre-defined level of current to represent the mark or space symbols. This is as opposed to the telephone system, which used differing voltages to encode frequency information. For this reason, telex exchanges were entirely separate from the system, with their own signalling standards, exchanges. When telephone and telex exchange equipment was co-located, which was not uncommon, Telex provided the first common medium for international record communications using standard signalling techniques and operating criteria as specified by the International Telecommunication Union. Customers on any telex exchange could deliver messages to any other, to lower line usage, telex messages were normally first encoded onto paper tape and then read into the line as quickly as possible. The system normally delivered information at 50 baud or approximately 66 words per minute encoded using the International Telegraph Alphabet No.2, Telex began in Germany as a research and development program in 1926 that became an operational teleprinter service in 1933. The service, operated by the Reichspost had a speed of 50 baud — approximately 66 words per minute, Telex service spread within Europe and around the world. By 1978, West Germany, including West Berlin, had 123,298 telex connections, long before automatic telephony became available, most countries, even in central Africa and Asia, had at least a few high-frequency telex links. Often, government postal and telegraph services initiated these radio links, the most common radio standard, CCITT R.44 had error-corrected retransmitting time-division multiplexing of radio channels. Most impoverished PTTs operated their telex-on-radio channels non-stop, to get the value from them. The cost of TOR equipment has continued to fall, modern cablegrams or telegrams actually operate over dedicated telex networks, using TOR whenever required. Telex served as the forerunner of modern fax, email, abbreviated English as used in texting originated with telex operators exchanging informal messages in real time — they became the first texters long before the introduction of mobile phones. Telex users could send the message to several places around the world at the same time, like email today. This involved transmitting the message via paper tape to the InfoMaster Computer, in this way, a single message could be sent to multiple distant Telex and TWX machines as well as delivering the same message to non-Telex and non-TWX subscribers via Western Union Mailgram. Telex messages are routed by addressing them to an address, e. g.14910 ERIC S. Solutions also exist for the routing of messages to different telex terminals within a subscriber organization, by using different terminal identities
13.
Minicomputer
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A minicomputer, or colloquially mini, is a class of smaller computers that developed in the mid-1960s and sold for much less than mainframe and mid-size computers from IBM and its direct competitors. The class formed a group with its own software architectures. Minis were designed for control, instrumentation, human interaction, and communication switching as distinct from calculation, many were sold indirectly to Original Equipment Manufacturers for final end use application. During the two decade lifetime of the class, almost 100 companies formed and only a half dozen remained. They usually took up one or a few 19-inch rack cabinets, the definition of minicomputer is vague with the consequence that there are a number of candidates for the first minicomputer. An early and highly successful minicomputer was Digital Equipment Corporations 12-bit PDP-8, later versions of the PDP-8 took advantage of small-scale integrated circuits. The important precursors of the PDP-8 include the PDP-5, LINC, the TX-0, the TX-2, DEC gave rise to a number of minicomputer companies along Massachusetts Route 128, including Data General, Wang Laboratories, Apollo Computer, and Prime Computer. Minicomputers were also known as midrange computers and they grew to have relatively high processing power and capacity. They were used in manufacturing process control, telephone switching and to control laboratory equipment, in the 1970s, they were the hardware that was used to launch the computer-aided design industry and other similar industries where a smaller dedicated system was needed. The 7400 series of TTL integrated circuits started appearing in minicomputers in the late 1960s, the 74181 arithmetic logic unit was commonly used in the CPU data paths. Each 74181 had a bus width of four bits, hence the popularity of bit-slice architecture, some scientific computers, such as the Nicolet 1080, would use the 7400 series in groups of five ICs for their uncommon twenty bits architecture. Starting in the 1980s, many minicomputers used VLSI circuits, the result was that minicomputers and computer terminals were replaced by networked workstations, file servers and PCs in some installations, beginning in the latter half of the 1980s. Also, the Microsoft Windows series of operating systems, beginning with Windows NT, now included server versions that supported preemptive multitasking, Digital Equipment Corporation was once the leading minicomputer manufacturer, at one time the second-largest computer company after IBM. DEC was sold to Compaq in 1998, while Data General was acquired by EMC Corporation, today only a few proprietary minicomputer architectures survive. The IBM System/38 operating system, which introduced many advanced concepts, realising the importance of the myriad lines of legacy code written, AS stands for Application System. Great efforts were made by IBM to enable programs written for the System/34. The AS/400 was replaced by the iSeries, which was replaced by the System i. In 2008, the System i was replaced by the IBM Power Systems, by contrast, competing proprietary computing architectures from the early 1980s, such as DECs VAX, Wang VS and Hewlett Packards HP3000 have long been discontinued without a compatible upgrade path
14.
World War II
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World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945, although related conflicts began earlier. It involved the vast majority of the worlds countries—including all of the great powers—eventually forming two opposing alliances, the Allies and the Axis. It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries. Marked by mass deaths of civilians, including the Holocaust and the bombing of industrial and population centres. These made World War II the deadliest conflict in human history, from late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, and formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Poland, Finland, Romania and the Baltic states. In December 1941, Japan attacked the United States and European colonies in the Pacific Ocean, and quickly conquered much of the Western Pacific. The Axis advance halted in 1942 when Japan lost the critical Battle of Midway, near Hawaii, in 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained all of its territorial losses and invaded Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in South Central China and Burma, while the Allies crippled the Japanese Navy, thus ended the war in Asia, cementing the total victory of the Allies. World War II altered the political alignment and social structure of the world, the United Nations was established to foster international co-operation and prevent future conflicts. The victorious great powers—the United States, the Soviet Union, China, the United Kingdom, the Soviet Union and the United States emerged as rival superpowers, setting the stage for the Cold War, which lasted for the next 46 years. Meanwhile, the influence of European great powers waned, while the decolonisation of Asia, most countries whose industries had been damaged moved towards economic recovery. Political integration, especially in Europe, emerged as an effort to end pre-war enmities, the start of the war in Europe is generally held to be 1 September 1939, beginning with the German invasion of Poland, Britain and France declared war on Germany two days later. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or even the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred simultaneously and this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935. The British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the forces of Mongolia and the Soviet Union from May to September 1939, the exact date of the wars end is also not universally agreed upon. It was generally accepted at the time that the war ended with the armistice of 14 August 1945, rather than the formal surrender of Japan
15.
KYW (AM)
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KYW, Newsradio 10-60, is a commercial AM radio station, licensed to Philadelphia, Pennsylvania. The station is owned by the CBS Radio subsidiary of CBS Corporation and its studios are located in Center City Philadelphia and its transmitter and two-tower directional antenna array are located in Lafayette Hill. KYW is one of the oldest radio stations in the United States, located in Chicago, Illinois at its start in late 1921, it moved to Philadelphia in 1934. In 1956 the KYW call letters were transferred to a station in Cleveland, Ohio, KYW uses HD Radio on its AM signal 24 hours a day. The stations programming is available via a simulcast on the HD2 subchannel of sister station WIP-FM. An assortment of local, national and global headlines are read at the top and bottom of each hour, an unusual characteristic of KYW is the playing of a recording of Teletype printers clattering in the background while KYW reporters announce at the studio. This is intended to allow listeners to identify the station to which they are listening. However, the sound is not played during other times, such as commercials and taped news segments, KFWB Los Angeles and WMAQ Chicago also used this branding until they changed formats. The station was first licensed on November 15,1921 as Chicagos first broadcasting station and it was initially jointly operated by Westinghouse and Commonwealth Edison, with Westinghouse later taking over as sole operator. Ten microphones were installed across the Chicago Civic Auditorium stage, with equipment for switching between them as needed, after the close of the opera season, KYW installed a studio in the Commonwealth Edison building, and began producing additional programming. By fall of 1922 the station was operating for twelve hours a day, Westinghouse had been a founding partner of RCA, NBCs original parent company. In 1923, Westinghouse established a station, KFKX in Hastings, Nebraska, in 1928 the project was abandoned, although it was announced that the KFKX programming was being consolidated with KYW, which resulted in the creation of the dual call letter assignment of KYW-KFKX. KFKX would be dropped from the call sign in 1933. Under the provisions of the Federal Radio Commissions General Order 40, KYW was assigned to the clear channel frequency of 1020 kHz, but the assignment caused two major problems. A second issue was that, under the provisions of the Davis Amendment, Chicago was located in Region 4, while the reallocation provisions had reserved 1020 kHz for use in Region 2, a grouping of mid-Atlantic states. Westinghouse fought a legal battle attempting to keep KYW operating on 1020 in Chicago. After broadcasting its last program in Chicago on December 2,1934, KYW gave its debut Philadelphia program the day, utilizing the studios. In 1938 KYWs studios were located at 1619 Walnut Street in Center City, in 1942, the Federal Communications Commission compelled RCA to divest itself of one of its two radio networks
16.
Teletype Model 28
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The Teletype Model 28 is more rugged and more expensive than later Teletype Model 32 machines. The Teletype Corporation introduced the Model 28 as a product in 1953 after being originally designed for the United States military. Teletype Corporations Model 28 line of communications terminals was first delivered to the US Military in 1951 and this series of teleprinters and associated equipment was popular in the various branches of the United States Armed Forces, and commercially in the financial and manufacturing industries. Teletype machines were replaced in new installations by dot-matrix printers. Basic CRT-based terminals which could only print lines and scroll them are called glass teletypes to distinguish them from more sophisticated devices. Teletype Corporation discontinued Model 28 production in 1981, while the manufacturer called the Model 28 teleprinter with a tape punch and tape reader a Model 28 ASR, many users, specifically computer users, called this equipment an ASR-28. This naming discrepancy continued from the Teletype Model 28 to other Teletype equipment in later DEC documentation, the design objective for the Model 28 was a machine that would run at 100 words-per-minute with less maintenance than that required by a contemporary teletypewriter running at 60 words-per-minute. Additional design criteria included the requirements to run quieter and be lighter than previous teleprinters, the Model 28 equipment was also designed to successfully operate in a wider range of temperatures and operate in moving vehicles. The Model 28 equipment adjustments are made by turning screws and not by bending metal bars and levers as is done in the later Model 32, the Model 28 printing unit frame is lighter due to the use of stamped sheet metal instead of cast iron. The Model 28 ASR allowed the user to operate the keyboard to punch tape while transmitting a previously punched tape, one of the design advances in the Model 28 is the use of a compact and lightweight type box. In the Model 15, the moving carriage assembly weighs slightly over five pounds, the carriage assembly in the Model 28 weighs eight ounces. This weight reduction allows for a carriage return, necessary for 100 word-per-minute operation. The lighter carriage assembly effectively eliminates the effect of gravity on operation in the air, the type box is easily removed, without tools, for cleaning and there are many type box options. Lists sixteen available Model 28 type box options, another design advance in the Model 28 was the use of a new all-steel clutch that uses internal expansion to minimize wear and reduce the need for lubrication. The Model 28 series was also modular, the keyboard unit, the printing unit, the perforators and the transmitter distributors are self-contained and easily swappable to aid in troubleshooting and maintenance. Forty-two functional control positions are provided, some of which as used for such as carriage return, line feed, figures shift, letters shift, unshift-on-space. The removable Electrical Service Unit is an integrated chassis housing the line fuse, convenience receptacle, terminal blocks for wiring options and mounting facilities for optional sub-assemblies. The Model 28 is usually geared to run at maximum speed ten characters per second speed, i. e.100 words-per-minute, but other speeds are available
17.
Teletype Model 33
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The Teletype Model 33 is an electromechanical teleprinter designed for light-duty office. It is less rugged and less expensive than earlier Teletype machines, the Teletype Corporation introduced the Model 33 as a commercial product in 1963 after being originally designed for the US Navy. The Model 33 was one of the first products to employ the then new ASCII code, a companion Model 32 used the more established five-level Baudot code. Because of its low price and ASCII-compatibility, the Model 33 was widely used with early minicomputers, Teletype Corporations Model 33 terminal, introduced in 1963, is one of the most popular terminals in the data-communications industry. Over a half-million Model 32s and 33s were made by 1975, a Model 33 cost about $700, much less than other teleprinters and computer terminals at the time, such as the Friden Flexowriter and the IBM1050. Early video terminals, such as the Tektronix 4010, did not become available until 1970, however the introduction of integrated circuits and semiconductor memory later that decade allowed the price of cathode-ray-tube-based terminals to fall below the price of a Teletype. Teletype machines were replaced in new installations by dot-matrix printers. Basic CRT-based terminals which could only print lines and scroll them are called glass teletypes to distinguish them from more sophisticated devices. Teletype Corporation discontinued Model 33 production in 1981, while the manufacturer called the Model 33 teleprinter with a tape punch and tape reader a Model 33 ASR, many users, specifically computer users, called this equipment an ASR-33. This naming discrepancy continued from the Teletype Model 28 to other Teletype equipment in later DEC documentation, for example, Digital Equipment Corporations PDP-15 Price List from April 1970 lists a number of Teletype Corporation teletypewriters using this alternate naming convention. This alternate naming convention was continued as other computer manufacturers published their documentation, for example, Micro Instrumentation and Telemetry Systems sold the Teletype Model 33 ASR as Teletype ASR-33. The design objective for the Model 33 was a machine that would fit into an office space, match with other office equipment of the time. Since this machine was designed for light duty use, adjustments that Teletype made in previous teleprinters by turning screws were made by bending metal bars and levers, many Model 33 parts were not heat treated and hardened. However, the base was die cast, but self-tapping screws were used, in another cost saving measure, the paper tape equipment was dependent on the keyboard and page printer mechanisms. Independent use of the tape punch and reader is not possible with the Model 33 ASR. The Model 33 used the seven-bit upper-case only ASCII code, also known as CCITT International Telegraphic Alphabet No,5, with one parity bit and two stop bits. The Model 33 is usually geared to run at maximum speed ten characters per second speed, i. e.100 words per minute, but other speeds are available,60 wpm,66 wpm,68.2 wpm, there were also many typewheel options. The Teletype Parts Bulletin lists sixty-nine available Model 33 typewheel options, the Teletype Model 33 contained an answer-back mechanism that was generally used in dial-up networks such as the TWX network
18.
ASCII
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ASCII, abbreviated from American Standard Code for Information Interchange, is a character encoding standard. ASCII codes represent text in computers, telecommunications equipment, and other devices, most modern character-encoding schemes are based on ASCII, although they support many additional characters. ASCII was developed from telegraph code and its first commercial use was as a seven-bit teleprinter code promoted by Bell data services. Work on the ASCII standard began on October 6,1960, the first edition of the standard was published in 1963, underwent a major revision during 1967, and experienced its most recent update during 1986. Compared to earlier telegraph codes, the proposed Bell code and ASCII were both ordered for more convenient sorting of lists, and added features for other than teleprinters. Originally based on the English alphabet, ASCII encodes 128 specified characters into seven-bit integers as shown by the ASCII chart above. The characters encoded are numbers 0 to 9, lowercase letters a to z, uppercase letters A to Z, basic punctuation symbols, control codes that originated with Teletype machines, for example, lowercase j would become binary 1101010 and decimal 106. ASCII includes definitions for 128 characters,33 are non-printing control characters that affect how text and space are processed and 95 printable characters, of these, the IANA encourages use of the name US-ASCII for Internet uses of ASCII. The ASA became the United States of America Standards Institute and ultimately the American National Standards Institute, there was some debate at the time whether there should be more control characters rather than the lowercase alphabet. The X3.2.4 task group voted its approval for the change to ASCII at its May 1963 meeting, the X3 committee made other changes, including other new characters, renaming some control characters and moving or removing others. ASCII was subsequently updated as USAS X3. 4-1967, then USAS X3. 4-1968, ANSI X3. 4-1977 and they proposed a 9-track standard for magnetic tape, and attempted to deal with some punched card formats. The X3.2 subcommittee designed ASCII based on the earlier teleprinter encoding systems, like other character encodings, ASCII specifies a correspondence between digital bit patterns and character symbols. This allows digital devices to communicate each other and to process, store. Before ASCII was developed, the encodings in use included 26 alphabetic characters,10 numerical digits, ITA2 were in turn based on the 5-bit telegraph code Émile Baudot invented in 1870 and patented in 1874. The committee debated the possibility of a function, which would allow more than 64 codes to be represented by a six-bit code. In a shifted code, some character codes determine choices between options for the character codes. It allows compact encoding, but is reliable for data transmission. The standards committee decided against shifting, and so ASCII required at least a seven-bit code, the committee considered an eight-bit code, since eight bits would allow two four-bit patterns to efficiently encode two digits with binary-coded decimal
19.
System console
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It is a physical device consisting of a keyboard and a screen, and traditionally is a text terminal, but may also be a graphical terminal. System consoles are generalized to computer terminals, which are abstracted respectively by virtual consoles, today communication with system consoles is generally done abstractly, via the standard streams, but there may be system-specific interfaces, for example those used by the system kernel. On traditional minicomputers, the console was a console, an RS-232 serial link to a terminal such as a DEC VT100. This terminal was kept in a secured room since it could be used for certain privileged functions such as halting the system or selecting which media to boot from. Large midrange systems, e. g. those from Sun Microsystems, Hewlett-Packard and IBM, in larger installations, the console ports are attached to multiplexers or network-connected multiport serial servers that let an operator connect a terminal to any of the attached servers. Today, serial consoles are used for accessing headless systems. Also, routers, enterprise network switches and other equipment have RS-232 serial console ports. On PCs and workstations, the computers attached keyboard and monitor have the equivalent function, since the monitor cable carries video signals, it cannot be extended very far. Often, installations with many servers therefore use keyboard/video multiplexers and possibly video amplifiers to centralize console access, in recent years, KVM/IP devices have become available that allow a remote computer to view the video output and send keyboard input via any TCP/IP network and therefore the Internet. Some PC BIOSes, especially in servers, also support serial consoles, even where BIOS support is lacking, some operating systems, e. g. FreeBSD and Linux, can be configured for serial console operation either during bootup, or after startup. It is usually possible to log in from the console, depending on configuration, the operating system may treat a login session from the console as being more trustworthy than a login session from other sources. Command-line interface Console application Console server Linux console Virtual console Win32 console
20.
Number One Electronic Switching System
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The Number One Electronic Switching System was the first large-scale stored program control telephone exchange or electronic switching system in the Bell System. It was manufactured by Western Electric and placed into service in Succasunna, New Jersey, the switching fabric was composed of a reed relay matrix controlled by wire spring relays which in turn were controlled by a central processing unit. The 1AESS central office switch incorporated higher processing capacities based on the 1A Processor in 1976, the voice switching fabric plan was similar to that of the earlier 5XB switch in being bidirectional and in using the call-back principle. The largest full access matrix switches in the system, however, were 8x8 rather than 10x10 or 20x16, thus they required eight stages rather than four to achieve large enough junctor groups in a large office. Crosspoints being more expensive in the new system but switches cheaper, the fabric was divided into Line Networks and Trunk Networks of four stages, and partially folded to allow connecting line-to-line or trunk-to-trunk without exceeding eight stages of switching. For a switch with 1000 input customers and 1000 output customers, when one considers that a large telephone system can have many more than 1000 x 1000 customers, the hardware to establish a full interconnection can grow rapidly and exceed practical implementations. Agner Krarup Erlang first theorized a compromise which is based upon the concept that not all lines are connected at the same time. From statistical theory, it is possible to design hardware that can connect most of the calls, in the sense of a high percentage and these are commonly referred to as blocking switches and are the most common in modern telephone exchanges. They are generally implemented as smaller switch fabrics in cascade, in many, a randomizer is used to select the start of a path through the multistage fabric so that the statistical properties predicted by the theory can be gained. Links were designated A, B, C, and J for Junctor, a Links were internal to the LSF or TSF, B Links connected LSF or TSF to JSF, C were internal to JSF, and J links or Junctors connected to another net in the exchange. All JSFs had a unity concentration ratio, that is the number of B links within the network equalled the number of junctors to other networks, most LSFs had a 4,1 Line Concentration Ratio, that is the lines were four times as numerous as the B links. In some urban areas 2,1 LSF were used, the B links were often multipled to make a higher LCR, such as 3,1 or 5,1. Line Networks always had 1024 Junctors, arranged in 16 grids that each switched 64 junctors to 64 B links, four grids were grouped for control purposes in each of four LJFs. TSF had a unity concentration, but a TN could have more TSFs than JSFs, thus their B links were usually multipled to make a Trunk Concentration Ratio of 1.25,1 or 1.5,1, the latter being especially common in 1A offices. TSFs and JSFs were identical except for their position in the fabric, each JSF or TSF was divided into 4 two-stage grids. Early TNs had four JSF, for a total of 16 grids,1024 J links, starting in the mid-1970s, larger offices had their B links wired differently, with only two B links from each Trunk Junctor Grid to each Trunk Switch Grid. This allowed a larger TN, with 8 JSF containing 32 grids, thus the junctor groups could be larger and more efficient. These TN had eight TSF, giving the TN a unity concentration ratio
21.
Rack-mounted
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A 19-inch rack is a standardized frame or enclosure for mounting multiple electronic equipment modules. Each module has a front panel that is 19 inches wide, the 19-inch dimension includes the edges, or ears, that protrude on each side which allow the module to be fastened to the rack frame with screws. Common uses include server, audio, and scientific lab equipment, the height of the electronic modules is also standardized as multiples of 1.752 inches or one rack unit or U. The industry standard rack cabinet is 42U tall, the term relay rack appeared first in the world of telephony. By 1911, the term was also being used in railroad signaling, there is little evidence that the dimensions of these early racks were standardized. The 19-inch rack format with rack-units of 1.75 inches was established as a standard by AT&T around 1922 in order to reduce the space required for repeater, the earliest repeaters from 1914 were installed in ad-hoc fashion on shelves, in wooden boxes and cabinets. Once serial production started, they were built into bespoke racks, the height of the different panels will vary, but in all cases to be a whole multiple of 1¾ inches. The 19-inch rack format has remained constant while the technology that is mounted within it has changed considerably, nineteen-inch racks in two-post or four-post form hold most equipment in modern data centers, ISP facilities, and professionally designed corporate server rooms. They allow for dense hardware configurations without occupying excessive floorspace or requiring shelving, nineteen-inch racks are also often used to house professional audio and video equipment, including amplifiers, effects units, interfaces, headphone amplifiers, and even small scale audio mixers. A third common use for rack-mounted equipment is industrial power, control, typically, a piece of equipment being installed has a front panel height 1⁄32 inch less than the allotted number of Us. Thus, a 1U rackmount computer is not 1.75 inches tall but is 1.719 inches tall, 2U would be 3.469 inches instead of 3.5 inches. This gap allows a bit of room above and below a piece of equipment so it may be removed without binding on the adjacent equipment. State-of-the-art rackmount cases are now constructed of thermo stamped composite, carbon fiber. Originally, the holes were tapped with a particular screw thread. Tapping large numbers of holes that may never be used is expensive, nonetheless tapped-hole racks are still in use, examples include telephone exchanges, network cabling panels, broadcast studios and some government and military applications. The tapped-hole rack was first replaced by clearance-hole racks, the holes are large enough to permit a bolt to be freely inserted through without binding, and bolts are fastened in place using cage nuts. In the event of a nut being stripped out or a bolt breaking, production of clearance-hole racks is less expensive because tapping the holes is eliminated and replaced with fewer, less expensive, cage nuts. The next innovation in design has been the square-hole rack
22.
RS-232
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In telecommunications, RS-232 is a standard for serial communication transmission of data. It formally defines the signals connecting between a DTE such as a terminal, and a DCE, such as a modem. The RS-232 standard is used in computer serial ports. The standard defines the characteristics and timing of signals, the meaning of signals. The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997. An RS-232 serial port was once a feature of a personal computer, used for connections to modems, printers, mice, data storage, uninterruptible power supplies. However, RS-232 is hampered by low speed, large voltage swing. In modern personal computers, USB has displaced RS-232 from most of its peripheral interface roles, nevertheless, RS-232 devices are still used, especially in industrial machines, networking equipment, and scientific instruments. Interface mechanical characteristics, pluggable connectors and pin identification, functions of each circuit in the interface connector. Standard subsets of interface circuits for selected telecom applications, the standard does not define such elements as the character encoding, the framing of characters, transmission order of bits, or error detection protocols. The character format and transmission bit rate are set by the serial port hardware which may also contain circuits to convert the internal logic levels to RS-232 compatible signal levels. The standard does not define bit rates for transmission, except that it says it is intended for bit rates lower than 20,000 bits per second, RS-232 was first introduced in 1960 by the Electronic Industries Association as a Recommended Standard. The original DTEs were electromechanical teletypewriters, and the original DCEs were modems, when electronic terminals began to be used, they were often designed to be interchangeable with teletypewriters, and so supported RS-232. The C revision of the standard was issued in 1969 in part to accommodate the electrical characteristics of these devices, the resulting common problems were non-standard pin assignment of circuits on connectors, and incorrect or missing control signals. The lack of adherence to the standards produced a thriving industry of breakout boxes, patch boxes, test equipment, books, a common deviation from the standard was to drive the signals at a reduced voltage. Some manufacturers therefore built transmitters that supplied +5 V and −5 V, later personal computers started to make use of the standard so that they could connect to existing equipment. For many years, an RS-232-compatible port was a feature for serial communications, such as modem connections. It remained in use into the late 1990s
23.
International Standard Book Number
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The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts of a 10-digit ISBN is also done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker
24.
Institute of Electrical and Electronics Engineers
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The Institute of Electrical and Electronics Engineers is a professional association with its corporate office in New York City and its operations center in Piscataway, New Jersey. It was formed in 1963 from the amalgamation of the American Institute of Electrical Engineers, today, it is the worlds largest association of technical professionals with more than 400,000 members in chapters around the world. Its objectives are the educational and technical advancement of electrical and electronic engineering, telecommunications, computer engineering, IEEE stands for the Institute of Electrical and Electronics Engineers. The association is chartered under this full legal name, IEEEs membership has long been composed of engineers and scientists. For this reason the organization no longer goes by the name, except on legal business documents. The IEEE is dedicated to advancing technological innovation and excellence and it has about 430,000 members in about 160 countries, slightly less than half of whom reside in the United States. The major interests of the AIEE were wire communications and light, the IRE concerned mostly radio engineering, and was formed from two smaller organizations, the Society of Wireless and Telegraph Engineers and the Wireless Institute. After World War II, the two became increasingly competitive, and in 1961, the leadership of both the IRE and the AIEE resolved to consolidate the two organizations. The two organizations merged as the IEEE on January 1,1963. The IEEE is incorporated under the Not-for-Profit Corporation Law of the state of New York and it was formed in 1963 by the merger of the Institute of Radio Engineers and the American Institute of Electrical Engineers. The IEEE serves as a publisher of scientific journals and organizer of conferences, workshops. IEEE develops and participates in activities such as accreditation of electrical engineering programs in institutes of higher learning. The IEEE logo is a design which illustrates the right hand grip rule embedded in Benjamin Franklins kite. IEEE has a dual complementary regional and technical structure – with organizational units based on geography and it manages a separate organizational unit which recommends policies and implements programs specifically intended to benefit the members, the profession and the public in the United States. The IEEE includes 39 technical Societies, organized around specialized technical fields, the IEEE Standards Association is in charge of the standardization activities of the IEEE. The IEEE History Center became an organization to the Engineering. The new ETHW is an effort by various engineering societies as a formal repository of topic articles, oral histories, first-hand histories, Landmarks + Milestones. The IEEE History Center is annexed to Stevens University Hoboken, NJ, in 2016, the IEEE acquired GlobalSpec, adding the provision of engineering data for a profit to its organizational portfolio
25.
International Standard Serial Number
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An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication. The ISSN is especially helpful in distinguishing between serials with the same title, ISSN are used in ordering, cataloging, interlibrary loans, and other practices in connection with serial literature. The ISSN system was first drafted as an International Organization for Standardization international standard in 1971, ISO subcommittee TC 46/SC9 is responsible for maintaining the standard. When a serial with the content is published in more than one media type. For example, many serials are published both in print and electronic media, the ISSN system refers to these types as print ISSN and electronic ISSN, respectively. The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers, as an integer number, it can be represented by the first seven digits. The last code digit, which may be 0-9 or an X, is a check digit. Formally, the form of the ISSN code can be expressed as follows, NNNN-NNNC where N is in the set, a digit character. The ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, for calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, the modulus 11 of the sum must be 0. There is an online ISSN checker that can validate an ISSN, ISSN codes are assigned by a network of ISSN National Centres, usually located at national libraries and coordinated by the ISSN International Centre based in Paris. The International Centre is an organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, at the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept, where ISBNs are assigned to individual books, an ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an identifier associated with a serial title. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change, separate ISSNs are needed for serials in different media. Thus, the print and electronic versions of a serial need separate ISSNs. Also, a CD-ROM version and a web version of a serial require different ISSNs since two different media are involved, however, the same ISSN can be used for different file formats of the same online serial
26.
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
27.
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
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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
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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
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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
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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
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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
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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
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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
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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
