The Baudot code[boˈdo] is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use until the advent of ASCII. Each character in the alphabet is represented by a series of five bits, sent over a communication channel such as a telegraph wire or a radio signal. The symbol rate measurement is known as baud, and is derived from the same name.
An electrical telegraph was a point-to-point text messaging system, used from the 1840s until the mid 20th century when it was slowly replaced by other telecommunication systems. At the sending station switches connected a source of current to the telegraph wires. At the receiving station the current activated electromagnets which moved indicators, providing either a visual or audible indication of the text. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems called telegraphs, that were devised to communicate text messages more rapidly than by physical transportation. Prior to the electric telegraph, semaphore systems were used, including beacons, smoke signals, flag semaphore, and optical telegraphs for visual signals to communicate over distances of land.
Jean-Maurice-Émile Baudot, French telegraph engineer and inventor of the first means of digital communication Baudot code, was one of the pioneers of telecommunications. He invented a multiplexed printing telegraph system that used his code and allowed multiple transmissions over a single line. The baud unit was named after him.
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from Greek: τῆλε and φωνή, together meaning distant voice. A common short form of the term is phone, which came into use almost immediately after the first patent was issued.
Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas pigeon post is not. Ancient signalling systems, although sometimes quite extensive and sophisticated as in China, were generally not capable of transmitting arbitrary text messages. Possible messages were fixed and predetermined and such systems are thus not true telegraphs.
A teleprinter is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Initially they were used in telegraphy, which developed in the late 1830s and 1840s as the first use of electrical engineering, though teleprinters were not used for telegraphy until 1887 at the earliest. The machines were adapted to provide a user interface to early mainframe computers and minicomputers, sending typed data to the computer and printing the response. Some models could also be used to create punched tape for data storage and to read back such tape for local printing or transmission.
Wireless telegraphy or radiotelegraphy is transmission of telegraph signals by radio waves. Before about 1910, the term wireless telegraphy was also used for other experimental technologies for transmitting telegraph signals without wires. In radiotelegraphy, information is transmitted by pulses of radio waves of two different lengths called "dots" and "dashes", which spell out text messages, usually in Morse code. In a manual system, the sending operator taps on a switch called a telegraph key which turns the transmitter on and off, producing the pulses of radio waves. At the receiver the pulses are audible in the receiver's speaker as beeps, which are translated back to text by an operator who knows Morse code.
Ernst Werner Siemens was a German electrical engineer, inventor and industrialist. Siemens's name has been adopted as the SI unit of electrical conductance, the siemens. He founded the electrical and telecommunications conglomerate Siemens.
The telautograph, an analog precursor to the modern fax machine, transmits electrical impulses recorded by potentiometers at the sending station to servomechanisms attached to a pen at the receiving station, thus reproducing at the receiving station a drawing or signature made by the sender. It was the first such device to transmit drawings to a stationary sheet of paper; previous inventions in Europe had used rotating drums to make such transmissions.
Elisha Gray was an American electrical engineer who co-founded the Western Electric Manufacturing Company. Gray is best known for his development of a telephone prototype in 1876 in Highland Park, Illinois. Some recent authors have argued that Gray should be considered the true inventor of the telephone because Alexander Graham Bell allegedly stole the idea of the liquid transmitter from him. Although Gray had been using liquid transmitters in his telephone experiments for more than two years previously, Bell's telephone patent was upheld in numerous court decisions.
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, 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 of International Morse Code.
David Edward Hughes, was a British-American inventor, practical experimenter, and professor of music known for his work on the printing telegraph and the microphone. He is generally considered to have been born in London but his family moved around that time so he may have been born in Corwen, Wales. His family moved to the U.S. while he was a child and he became a professor of music in Kentucky. In 1855 he patented a printing telegraph. He moved back to London in 1857 and further pursued experimentation and invention, coming up with an improved carbon microphone in 1878. In 1879 he identified what seemed to be a new phenomenon during his experiments: sparking in one device could be heard in a separate portable microphone apparatus he had set up. It was most probably radio transmissions but this was nine years before electromagnetic radiation was a proven concept and Hughes was convinced by others that his discovery was simply electromagnetic induction.
The Electric Telegraph Company (ETC) was a British telegraph company founded in 1846 by William Fothergill Cooke and John Ricardo. It was the world's first public telegraph company. The equipment used was the Cooke and Wheatstone telegraph, an electrical telegraph developed a few years earlier in collaboration with Charles Wheatstone. The system had been taken up by several railway companies for signalling purposes, but in forming the company Cooke intended to open up the technology to the public at large.
The history of telecommunication began with the use of smoke signals and drums in Africa, Asia, and the Americas. In the 1790s, the first fixed semaphore systems emerged in Europe. However, it was not until the 1830s that electrical telecommunication systems started to appear. 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 larger history of communication.
The Teletype Corporation, a part of American Telephone and Telegraph Company's Western Electric manufacturing arm since 1930, came into being in 1928 when the Morkrum-Kleinschmidt Company changed its name to the name of its trademark equipment. Teletype Corporation, of Skokie, Illinois, was responsible for the research, development and manufacture of data and record communications equipment, but it is primarily remembered for the manufacture of electromechanical teleprinters.
The printing telegraph was invented by Royal Earl House in 1846. House's equipment could transmit around 40 instantly readable words per minute, but was difficult to manufacture in bulk. 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.
Henry Sutton was an Australian designer, engineer, and inventor credited with contributions to early developments in electricity, aviation, wireless communication, photography and telephony.
Semaphore is the use of an apparatus to create a visual signal transmitted over distance. A semaphore can be performed with devices including: fire, lights, flags, sunlight and moving arms. Semaphores can be used for telegraphy when arranged in visually connected networks, or for traffic signalling such as in railway systems, or traffic lights in cities.
Lloyd Espenschied was an American electrical engineer who invented the modern coaxial cable with Herman Andrew Affel.
In the nineteenth century, the United Kingdom had the world's first commercial telegraph company. British telegraphy dominated international telecommunications well into the twentieth. Telegraphy is the sending of textual messages by human operators using symbolic codes. Electrical telegraphy used conducting wires to send messages, often incorporating a telegram service to deliver the telegraphed communication from the telegraph office. This is distinct from optical telegraphy that preceded it and the radiotelegraphy that followed. Though Francis Ronalds first demonstrated a working telegraph over a substantial distance in 1816, he was unable to put it into practical use. Starting in 1836, William Fothergill Cooke, with the scientific assistance of Charles Wheatstone, developed the Cooke and Wheatstone telegraph. The needle telegraph instrument suggested by Wheatstone, the battery invented by John Frederic Daniell, and the relay invented by Edward Davy were important components of this system.
