Purpose of this Document

The purpose of this document is to delineate, in an organized fashion, the protocols used by Aircraft Communication Addressing and Reporting System (ACARS) Management Units (MU) defined in ARINC Characteristics 724B and 758 Communication Management Unit in their interactions with other onboard avionics equipment.

COMMENTARY

The interfaces described herein have evolved over time. The definitions are constrained to the most recent or most appropriate function. Some existing equipment, designed under earlier guidelines, will not comply with all of the provisions within this document. These interfaces should be updated by the user if practical, at his convenience, to the current standard to minimize interface incompatibilities.

ARINC 597, adopted in 1978, and ARINC 724, adopted in 1979 have been superseded by ARINC 724B and ARINC 758. Consequently, their status has been downgraded from Active to Legacy.