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Telegraph Code
A telegraph code is one of the character encodings used to transmit information by telegraphy. Morse code is the best-known such code. ''Telegraphy'' usually refers to the electrical telegraph, but telegraph systems using the optical telegraph were in use before that. A code consists of a number of code points, each corresponding to a letter of the alphabet, a numeral, or some other character. In codes intended for machines rather than humans, code points for control characters, such as carriage return, are required to control the operation of the mechanism. Each code point is made up of a number of elements arranged in a unique way for that character. There are usually two types of element (a binary code), but more element types were employed in some codes not intended for machines. For instance, American Morse code had about five elements, rather than the two (dot and dash) of International Morse Code. Codes meant for human interpretation were designed so that the characte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Character Encoding
Character encoding is the process of assigning numbers to graphical character (computing), characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using computers. The numerical values that make up a character encoding are known as code points and collectively comprise a code space or a code page. Early character encodings that originated with optical or electrical telegraphy and in early computers could only represent a subset of the characters used in written languages, sometimes restricted to Letter case, upper case letters, Numeral system, numerals and some punctuation only. Over time, character encodings capable of representing more characters were created, such as ASCII, the ISO/IEC 8859 encodings, various computer vendor encodings, and Unicode encodings such as UTF-8 and UTF-16. The Popularity of text encodings, most popular character encoding on the World Wide Web is UTF-8, which is used in 98.2% of surve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UTF-8
UTF-8 is a character encoding standard used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode Transformation Format 8-bit''. Almost every webpage is transmitted as UTF-8. UTF-8 supports all 1,112,064 valid Unicode code points using a variable-width encoding of one to four one- byte (8-bit) code units. Code points with lower numerical values, which tend to occur more frequently, are encoded using fewer bytes. It was designed for backward compatibility with ASCII: the first 128 characters of Unicode, which correspond one-to-one with ASCII, are encoded using a single byte with the same binary value as ASCII, so that a UTF-8-encoded file using only those characters is identical to an ASCII file. Most software designed for any extended ASCII can read and write UTF-8, and this results in fewer internationalization issues than any alternative text encoding. UTF-8 is dominant for all countries/languages on the internet, with 99% global ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Civil War
The American Civil War (April 12, 1861May 26, 1865; also known by Names of the American Civil War, other names) was a civil war in the United States between the Union (American Civil War), Union ("the North") and the Confederate States of America, Confederacy ("the South"), which was formed in 1861 by U.S. state, states that had Secession in the United States, seceded from the Union. The Origins of the American Civil War, central conflict leading to war was a dispute over whether Slavery in the United States, slavery should be permitted to expand into the western territories, leading to more slave states, or be prohibited from doing so, which many believed would place slavery on a course of ultimate extinction. Timeline of events leading to the American Civil War, Decades of controversy over slavery came to a head when Abraham Lincoln, who opposed slavery's expansion, won the 1860 presidential election. Seven Southern slave states responded to Lincoln's victory by seceding f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Compaction
In telecommunications, data compaction is the reduction of the number of data elements, bandwidth, cost, and time for the generation, transmission, and storage of data without loss of information by eliminating unnecessary redundancy, removing irrelevancy, or using special coding. Examples of data compaction methods are the use of fixed- tolerance bands, variable-tolerance bands, slope-keypoints, sample changes, curve patterns, curve fitting, variable- precision coding, frequency analysis, and probability analysis. Simply squeezing noncompacted data into a smaller space, for example by increasing packing density by transferring images from newsprint to microfilm or by transferring data on punched cards onto magnetic tape, is not data compaction. Everyday examples The use of acronyms in texting is an everyday example. The number of bits required to transmit and store " WYSIWYG" (What You See Is What You Get) is reduced from its expanded equivalent (7 characters vs 28 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abraham Niclas Edelcrantz
Abraham Niclas Edelcrantz (born Clewberg; 28 July 1754 – 15 March 1821) was a Finnish-born Swedish poet and inventor. He was a member of the Swedish Academy, chair 2, from 1786 to 1821. Edelcrantz was the librarian at The Royal Academy of Turku. In 1783 he moved to Stockholm to lead the Royal Theater and later work as the private secretary of the king Gustaf III. He is known for his experiment with the optical telegraph. He inaugurated his telegraph with a poem dedicated to the Swedish King on his birthday in 1794. The message went from the Palace in Stockholm to the King at Drottningholm. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paris Postal Museum
Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of cities in the European Union by population within city limits, fourth-most populous city in the European Union and the List of cities proper by population density, 30th most densely populated city in the world in 2022. Since the 17th century, Paris has been one of the world's major centres of finance, diplomacy, commerce, culture, Fashion capital, fashion, and gastronomy. Because of its leading role in the French art, arts and Science and technology in France, sciences and its early adoption of extensive street lighting, Paris became known as the City of Light in the 19th century. The City of Paris is the centre of the Île-de-France region, or Paris Region, with an official estimated population of 12,271,794 inhabitants in January 2023, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lille
Lille (, ; ; ; ; ) is a city in the northern part of France, within French Flanders. Positioned along the Deûle river, near France's border with Belgium, it is the capital of the Hauts-de-France Regions of France, region, the Prefectures in France, prefecture of the Nord (French department), Nord Departments of France, department, and the main city of the Métropole Européenne de Lille, European Metropolis of Lille. The city of Lille proper had a population of 236,234 in 2020 within its small municipal territory of , but together with its French suburbs and exurbs the Lille metropolitan area (French part only), which extends over , had a population of 1,515,061 that same year (January 2020 census), the fourth most populated in France after Paris, Lyon, and Marseille. The city of Lille and 94 suburban French municipalities have formed since 2015 the Métropole Européenne de Lille, European Metropolis of Lille, an Indirect election, indirectly elected Métropole, metropolitan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Code Book
A codebook is a type of document used for gathering and storing cryptography codes. Originally, codebooks were often literally , but today "codebook" is a byword for the complete record of a series of codes, regardless of physical format. Cryptography In cryptography, a codebook is a document used for implementing a code. A codebook contains a lookup table for coding and decoding; each word or phrase has one or more strings which replace it. To decipher messages written in code, corresponding copies of the codebook must be available at either end. The distribution and physical security of codebooks presents a special difficulty in the use of codes compared to the secret information used in ciphers, the key, which is typically much shorter. The United States National Security Agency documents sometimes use ''codebook'' to refer to block ciphers; compare their use of ''combiner-type algorithm'' to refer to stream ciphers. Codebooks come in two forms, one-part or two-part: * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flag Semaphore
Flag semaphore (from the Ancient Greek () 'sign' and - (-) '-bearer') is a semaphore system conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags; it is read when the flag is in a fixed position. Semaphores were adopted and widely used (with hand-held flags replacing the mechanical arms of semaphore line, shutter semaphores) in the maritime world in the 19th century. It is still used during underway replenishment at sea and is acceptable for emergency communication in daylight or using lighted wands instead of flags, at night. Contemporary semaphore flag system The current flag semaphore system uses two short poles with square flags, which a signal person holds in different positions to signal letters of the alphabet and numbers. The signaller holds one pole in each hand, and extends each arm in one of eight possible directions. Except ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Admiralty
The Admiralty was a Departments of the Government of the United Kingdom, department of the Government of the United Kingdom that was responsible for the command of the Royal Navy. Historically, its titular head was the Lord High Admiral of the United Kingdom, Lord High Admiral – one of the Great Officers of State. For much of its history, from the early Admiralty in the 18th century, 18th century until its abolition, the role of the Lord High Admiral was almost invariably put "in commission" and exercised by the Lords Commissioner of the Admiralty, who sat on the governing Board of Admiralty, rather than by a single person. The Admiralty was replaced by the Admiralty Board (United Kingdom), Admiralty Board in 1964, as part of the reforms that created the Ministry of Defence (United Kingdom), Ministry of Defence and its Navy Department (Ministry of Defence), Navy Department (later Navy Command (Ministry of Defence), Navy Command). Before the Acts of Union 1707, the Office of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claude Chappe
Claude Chappe (; 25 December 1763 – 23 January 1805) was a French inventor who in 1792 demonstrated a practical semaphore line, semaphore system that eventually spanned all of France. His system consisted of a series of towers, each within line of sight of others, each supporting a wooden mast with two crossarms on pivots that could be placed in various positions. The operator in a tower moved the arms to a sequence of positions, spelling out text messages in semaphore code. The operator in the next tower read the message through a telescope, then passed it on to the next tower. This was the first practical telecommunications system of the industrial age, and was used until the 1850s when electric telegraph systems replaced it. Early life Claude Chappe was born in Brûlon, Sarthe, France, the son of Ignace Chappe, a ''contrôleur'' (Intendant (government official), intendant) of the Crown lands of France, Crown lands for Laval, Mayenne, Laval, and his wife Marie Devernay, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
