In telecommunication, the term data link has the following meanings:

1. The means of connecting one location to another for the purpose of transmitting and receiving data.
2. An assembly, consisting of parts of two data terminal equipments (DTEs) and the interconnecting data circuit, that is controlled by a link protocol enabling data to be transferred from a data source to a data sink.

Sources

• Federal Standard 1037C
• MIL-STD-188
• Department of Defense Dictionary of Military and Associated Terms