The smoke signal is one of the oldest forms of long-distance communication. It is a form of visual communication used over a long distance. In general smoke signals are used to transmit news, signal danger, or to gather people to a common area.
The smoke signal is one of the oldest forms of long-distance communication. It is a form of visual communication used over a long distance. In general smoke signals are used to transmit news, signal danger, or to gather people to a common area.
In ancient China, soldiers along the Great Wall sent smoke signals on its beacon towers to warn one another of enemy invasion. [1] [2] The colour of the smoke communicated the size of the invading party. [1] By placing the beacon towers at regular intervals, and situating a soldier in each tower, messages could be transmitted over the entire 7,300 kilometres of the Wall. [1] Smoke signals also warned the inner castles of the invasion, allowing them to coordinate a defense and garrison supporting troops. [2]
During the Kandyan period, soldiers stationed on the mountain peaks alerted each other of impending enemy attack (from English, Dutch or Portuguese people) by signaling from peak to peak. In this way, they could transmit a message to the King in just a few hours. [3] [ failed verification ]
Misuse of the smoke signal is traditionally considered to have contributed to the fall of the Western Zhou dynasty in the 8th century BCE. King You of Zhou was said to have had a habit of fooling his warlords with false warning beacons to amuse Bao Si, his concubine. [4]
North American indigenous peoples also communicated via smoke signal. Each tribe had its own signaling system and understanding. A signaler started a fire on an elevation typically using damp grass, which caused a column of smoke to rise. The grass was taken off as it dried and another bundle was placed on the fire. Reputedly the location of the smoke along the incline conveyed a meaning. If it came from halfway up the hill, it signaled that all was well; but from the top of the hill, it signified danger. [5]
Smoke signals remain in use today. The College of Cardinals uses smoke signals to indicate the selection of a new Pope during a papal conclave. Eligible cardinals conduct a secret ballot until someone receives a vote of two-thirds plus one. The ballots are burned after each vote. Black smoke indicates a failed ballot, and white smoke means a new Pope has been elected.
Colored smoke grenades are commonly used by military forces to mark positions, especially during calls for artillery or air support.
Smoke signals may also refer to smoke-producing devices used to send distress signals. [6] [7]
Lewis and Clark's journals cite several occasions when they adopted the Native American method of setting the plains on fire to communicate the presence of their party or their desire to meet with local tribes. [8]
Yámanas of South America used fire to send messages by smoke signals, for instance if a whale drifted ashore. [9] The large amount of meat required notification of many people so that it would not be wasted. [10] They might also have used smoke signals on other occasions—thus it is possible that Magellan saw such fires and was inspired to name the landscape Tierra del Fuego ("Land of Fire"); however, he may have seen the smoke or lights of natural phenomena. [11] [12]
The Cape Town Noon Gun, specifically the smoke its firing generates, was used to set marine chronometers in Table Bay.
Aboriginal Australians throughout Australia have used smoke signals for various purposes— [13] [14] [15] [16] sometimes to notify others of their presence, particularly when entering lands which were not their own. [13] Sometimes used to describe visiting Whites, smoke signals were the fastest way to send messages. [16] Smoke signals were sometimes used to notify of incursions by hostile tribes, or to arrange meetings between hunting parties of the same tribe. This signal could be from a fixed lookout on a ridge or from a mobile band of tribesman. [15] "Putting up a smoke" often promoted nearby individuals or groups to reply with their own signals. [14] [15] Different colours of smoke (black, white or blue, depending on whether the material being burnt was wet grass, dry grass, reeds or other materials) were used to convert information, as was the smoke's shape (a column, ball or ring), allowing a messaging system sophisticated enough to include the names of individual tribesmen. [15] Like other means of communication, signals could be misinterpreted. In one recorded instance, a smoke signal reply translated as "we are coming" was misinterpreted as joining a war party for protection of the tribe, when it was actually to indicate hunting parties coming together after a successful hunt. [15]
Modern aviation has made skywriting possible.
A beacon is an intentionally conspicuous device designed to attract attention to a specific location. A common example is the lighthouse, which draws attention to a fixed point that can be used to navigate around obstacles or into port. More modern examples include a variety of radio beacons that can be read on radio direction finders in all weather, and radar transponders that appear on radar displays.
Digital data, in information theory and information systems, is information represented as a string of discrete symbols, each of which can take on one of only a finite number of values from some alphabet, such as letters or digits. An example is a text document, which consists of a string of alphanumeric characters. The most common form of digital data in modern information systems is binary data, which is represented by a string of binary digits (bits) each of which can have one of two values, either 0 or 1.
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, so such systems are thus not true telegraphs.
A message is a discrete unit of communication intended by the source for consumption by some recipient or group of recipients. A message may be delivered by various means, including courier, telegraphy, or an electronic bus. A message can be the content of a broadcast. An interactive exchange of messages forms a conversation. The consumption of the message relies on how the recipient interprets the message, there are times where the recipient contradicts the intention of the message which results in a boomerang effect. Message fatigue is another outcome recipients can obtain if a message is conveyed too much by the source.
Tactical communications are military communications in which information of any kind, especially orders and military intelligence, are conveyed from one command, person, or place to another upon a battlefield, particularly during the conduct of combat. It includes any kind of delivery of information, whether verbal, written, visual or auditory, and can be sent in a variety of ways. In modern times, this is usually done by electronic means. Tactical communications do not include communications provided to tactical forces by the Defense Communications System to non-tactical military commands, to tactical forces by civil organizations, nor does it include strategic communication.
In radio communication, a transceiver is an electronic device which is a combination of a radio transmitter and a receiver, hence the name. It can both transmit and receive radio waves using an antenna, for communication purposes. These two related functions are often combined in a single device to reduce manufacturing costs. The term is also used for other devices which can both transmit and receive through a communications channel, such as optical transceivers which transmit and receive light in optical fiber systems, and bus transceivers which transmit and receive digital data in computer data buses.
An emergency position-indicating radiobeacon (EPIRB) is a type of emergency locator beacon for commercial and recreational boats, a portable, battery-powered radio transmitter used in emergencies to locate boaters in distress and in need of immediate rescue. In the event of an emergency, such as a ship sinking or medical emergency onboard, the transmitter is activated and begins transmitting a continuous 406 MHz distress radio signal, which is used by search-and-rescue teams to quickly locate the emergency and render aid. The signal is detected by satellites operated by an international consortium of rescue services, COSPAS-SARSAT, which can detect emergency beacons anywhere on Earth transmitting on the distress frequency of 406 MHz. The satellites calculate the position or utilize the GPS coordinates of the beacon and quickly passes the information to the appropriate local first responder organization, which performs the search and rescue. As Search and Rescue approach the search areas, they use Direction Finding (DF) equipment to locate the beacon using the 121.5 MHz homing signal, or in newer EPIRBs, the AIS location signal. The basic purpose of this system is to help rescuers find survivors within the so-called "golden day" during which the majority of survivors can usually be saved. The feature distinguishing a modern EPIRB, often called GPIRB, from other types of emergency beacon is that it contains a GPS receiver and broadcasts its position, usually accurate within 100 m (330 ft), to facilitate location. Previous emergency beacons without a GPS can only be localized to within 2 km (1.2 mi) by the COSPAS satellites and relied heavily upon the 121.5 MHz homing signal to pin-point the beacons location as they arrived on scene.
Optical communication, also known as optical telecommunication, is communication at a distance using light to carry information. It can be performed visually or by using electronic devices. The earliest basic forms of optical communication date back several millennia, while the earliest electrical device created to do so was the photophone, invented in 1880.
A distress signal, also known as a distress call, is an internationally recognized means for obtaining help. Distress signals are communicated by transmitting radio signals, displaying a visually observable item or illumination, or making a sound audible from a distance.
The Selk'nam, also known as the Onawo or Ona people, are an indigenous people in the Patagonian region of southern Argentina and Chile, including the Tierra del Fuego islands. They were one of the last native groups in South America to be encountered by migrant Europeans in the late 19th century. In the mid-19th century, there were about 4,000 Selk'nam; in 1916 Charles W. Furlong estimated there were about 800 Selk'nam living in Tierra del Fuego; with Walter Gardini stating that by 1919 there were 279, and by 1930 just over 100.
The communication with extraterrestrial intelligence (CETI) is a branch of the search for extraterrestrial intelligence (SETI) that focuses on composing and deciphering interstellar messages that theoretically could be understood by another technological civilization. The best-known CETI experiment of its kind was the 1974 Arecibo message composed by Frank Drake.
A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow for simultaneous communication in both directions between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field. There are two types of duplex communication systems: full-duplex (FDX) and half-duplex (HDX).
In software architecture, a messaging pattern is an architectural pattern which describes how two different parts of an application, or different systems connect and communicate with each other. There are many aspects to the concept of messaging which can be divided in the following categories: hardware device messaging and software data exchange. Despite the difference in the context, both categories exhibit common traits for data exchange.
H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. The H.323 standard addresses call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multi-point conferences.
Fuegians are the indigenous inhabitants of Tierra del Fuego, at the southern tip of South America. The name has been credited to Captain James Weddell, who supposedly created the term in 1822.
Phryctoria was a semaphore system used in Ancient Greece. The phryctoriae were towers built on selected mountaintops so that one tower (phryctoria) would be visible to the next tower. The towers were used for the transmission of a specific prearranged message. One tower would light its flame, the next tower would see the fire, and light its own.
A hydraulic telegraph refers to two different semaphore systems involving the use of water-based mechanisms as a telegraph. The earliest one was developed in 4th-century BC Greece, while the other was developed in 19th-century AD Britain. The Greek system was deployed in combination with semaphoric fires, while the latter British system was operated purely by hydraulic fluid pressure.
Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates oscillating electrical energy, often characterized as a wave. They can be received by other antennas connected to a radio receiver; this is the fundamental principle of radio communication. In addition to communication, radio is used for radar, radio navigation, remote control, remote sensing, and other applications.
An emergency communication system (ECS) is any system that is organized for the primary purpose of supporting one-way and two-way communication of emergency information between both individuals and groups of individuals. These systems are commonly designed to convey information over multiple types of devices, from signal lights to text messaging to live, streaming video, forming a unified communication system intended to optimize communications during emergencies. Contrary to emergency notification systems, which generally deliver emergency information in one direction, emergency communication systems are typically capable of both initiating and receiving information between multiple parties. These systems are often made up of both input devices, sensors, and output/communication devices. Therefore, the origination of information can occur from a variety of sources and locations, from which the system will disseminate that information to one or more target audiences.
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.
