Purpose of this Document

This specification contains a compendium of provisions previously defined in ARINC Characteristics 546, 566, 716, 597, 724, and 724B. These characteristics contained redundant material which, when updated at various times, created contradictions and confusion as to which text was correct.

The purpose of this specification is to bring this redundant material into one document which should serve as the description of operation within the ACARS air/ground environment. This specification also serves to clarify contradictions in the above-mentioned documents and present new material which will bring the overall ACARS documentation into the current state which it has evolved over many years. The provisions listed herein are included by reference in the originating documents as appropriate and, therefore, continue to apply as provisions of systems described in the originating documents.

In this document a reference to ARINC Characteristic 724/B refers to both ARINC Characteristic 724 and ARINC Characteristic 724B.