Interface standard

In telecommunication, an interface standard is a standard that describes one or more functional characteristics (such as code conversion, line assignments, or protocol compliance) or physical characteristics (such as electrical, mechanical, or optical characteristics) necessary to allow the exchange of information between two or more (usually different) systems or equipment.

Note 1: An interface standard may include operational characteristics and acceptable levels of performance.

Note 2: In the military community, interface standards permit command and control functions to be performed using communication and computer systems.

Source: from Federal Standard 1037C