Editing Data link

{{Short description|Means of connecting one location to another in order to transmit information between them}}
{{about|links for digital data transmission|other uses (including the network layer)}}
{{No footnotes|date=October 2008}}

A '''data link''' is a means of [[telecommunications link|connecting one location to another]] for the purpose of transmitting and receiving digital information ([[data communication]]). It can also refer to a set of electronics assemblies, consisting of a transmitter and a receiver (two pieces of [[data terminal equipment]]) and the interconnecting data [[telecommunication circuit]]. 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]]s, most commonly meaning all communications in one direction only.
* [[Half-duplex]] communications, meaning communications in both directions, but not both ways simultaneously.
* [[Duplex (telecommunications)|Duplex communications]], communications in both directions simultaneously.

==Aviation==
In civil [[aviation]], a data-link system (known as [[Controller Pilot Data Link Communications]]) is used to send information between aircraft and [[air traffic control]]lers for example when an aircraft is too far from the ATC to make voice radio communication and [[radar]] observations possible. Such systems are used for aircraft crossing the [[Atlantic]], [[Pacific]] and [[Indian Ocean|Indian]] oceans. One such system, used by [[Nav Canada]] and [[NATS Holdings|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]], land vehicles, boats, and spacecraft, a two-way ([[full-duplex]] or [[half-duplex]]) data-link is used to send [[control system|control signals]], and to receive [[telemetry]].

==See also==
* [[ACARS]]
* [[NASA Deep Space Network]]
* [[Space probe]]
* [[Tactical data link]]
* [[Terminal (telecommunication)]]
* [[Timex Datalink]]
* [[Unmanned aerial vehicle]]

==Sources==
*{{FS1037C MS188}}
*{{DODDIC}}

{{Telecommunications}}
{{Authority control}}

[[Category:Data transmission]]