A data link is the means of connecting one location to another for the purpose of transmitting and receiving digital information (

data communication Data transmission and data reception or, more broadly, data communication or digital communications is the transfer and reception of data in the form of a digital bitstream or a digitized analog signal transmitted over a point-to-point or ...

). It can also refer to a set of electronics assemblies, consisting of a transmitter and a receiver (two pieces of

data terminal equipment Data terminal equipment (DTE) is an end instrument that converts user information into signals or reconverts received signals. These can also be called tail circuits. A DTE device communicates with the data circuit-terminating equipment (DCE) ...

) and the interconnecting data

telecommunication circuit A telecommunication circuit is a path in a telecommunications network used to transmit information. Circuits have evolved over time from generally being built on physical connections between individual hardware cables, as in an analog phone swi ...

. These are governed by a link protocol enabling digital data to be transferred from a data source to a data sink.

Types

There are at least three types of basic data-link configurations that can be conceived of and used: *

Simplex communication Simplex communication is a communication channel that sends information in one direction only."Simplex" ''The IEEE Authoritative Dictionary of Standard Terms, 7th Ed.'', 2000, Inst. of Electrical and Electronic Engineers, p.1053 The Internationa ...

s, most commonly meaning all communications in one direction only. *

Half-duplex 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 ...

communications, meaning communications in both directions, but not both ways simultaneously. * Duplex communications, communications in both directions simultaneously.

Aviation

In civil

aviation Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as hot a ...

, a data-link system (known as

Controller Pilot Data Link Communications Controller may refer to: Occupations * Controller or financial controller, or in government accounting comptroller, a senior accounting position * Controller, someone who performs agent handling in espionage * Air traffic controller, a person w ...

) is used to send information between aircraft and

air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airs ...

lers for example when an aircraft is too far from the ATC to make voice radio communication and

radar Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, we ...

observations possible. Such systems are used for aircraft crossing the

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

and

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

oceans. One such system, used by

Nav Canada Nav Canada (styled as NAV CANADA) is a privately run, not-for-profit corporation that owns and operates Canada's civil air navigation system (ANS). It was established in accordance with the ''Civil Air Navigation Services Commercialization Act ...

and NATS over the North Atlantic, uses a five-digit data link sequence number confirmed between air traffic control and the pilots of the aircraft before the aircraft proceeds to cross the ocean. This system uses the aircraft's flight management computer to send location, speed and altitude information about the aircraft to the ATC. ATC can then send messages to the aircraft regarding any necessary change of course. In

unmanned aircraft An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...

, land vehicles, boats, and spacecraft, a two-way (

full-duplex 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 ...

half-duplex 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 ...

) data-link is used to send control signals, and to receive

telemetry Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', "remote", an ...

Sources

* * Data transmission {{telecom-stub

Types

Aviation

See also

Sources