Purpose of this Document

This document defines the air transport industry's standards for the transfer of aperiodic digital data between avionics systems elements. Adherence to these standards is desired for all inter-systems communications in which the system line replaceable units are defined as "unit interchangeable" in the relevant ARINC equipment Characteristics. Their use for intra-system communications in systems in which the line replaceable units are defined in the ARINC equipment Characteristics as "system interchangeable" is not essential, although it may be convenient.