ARINC 724 : 1988

1.0 INTRODUCTION
1.1 Purpose of this Document
1.2 Airborne Sub-System Configuration
1.3 Interchangeability
1.4 Regulatory Approval
2.0 INTERCHANGEABILITY STANDARDS
2.1 Introduction
2.2 Form Factors, Connectors and Index Pin Coding
2.3 Standard Interwiring
2.4 Primary Power Input
2.5 System Functions and Signal Characteristics
2.6 Environmental Conditions
2.7 Cooling
2.8 Grounding and Bonding
2.9 Standardized Signaling
3.0 SYSTEM DESIGN
3.1 Introduction
4.0 MANAGEMENT UNIT DESIGN
4.1 Decoding
4.2 Synchronization
4.3 Uplink Preamble Processing
4.4 Uplink BCS Check
4.5 Input/Output Interfaces
4.6 Universal Coordinated Time (UTC) Clock
4.7 MU Discrete Inputs and Outputs and Program Pins
4.8 Downlink Message Formats
4.9 Priorities
4.10 Polled Mode/Demand Mode Changeover
4.11 Downlink Preamble Generation
4.12 Downlink Message Assembly
4.13 Modulation
4.14 Radio Transmitter Keying
4.15 Radio Transceiver Tuning
4.16 Remaining Downlink Traffic Disposition
4.17 MU Interfaces for DFDAU and Flight Management Computers
4.18 DFDAU Message Formats
4.19 Data Transfer To/From Satellite Data Unit (SDU)
5.0 CONTROL UNIT DESIGN
5.1 Numeric Data Entry Facilities
5.2 Alpha Data Entry Facilities
5.3 Function Key Operation
5.4 Voice/Data Switch
5.5 Display Call Up to Key Operation
5.6 Annunciators
5.7 CU-to-MU Data Transfer
5.8 Display Provisions
6.0 PROVISIONS FOR TEST
6.1 Automatic Test Equipment (ATE) Provisions
6.2 Built-In-Test Equipment (BITE)
ATTACHMENTS
1-1 Airborne Sub-system Block Diagram
1-2 Management Unit Connector Positioning
1-3 Control Unit Connector Positioning
1-4 Control Unit - Typical Panel Layout
2-1 Standard Interwiring
2-2 Notes Applicable to the Standard Interwiring
2-3 Connector Insert Layout
3 Environmental Test Categories
4 Frequency Control
5 Serial Digital Channel Selection
APPENDIX
A OAT Design 'B'
B Voice to Data Channel Changeover

Specifies the 'Mark 2' version of the airborne components of the Aircraft Communications Addressing and Reporting System (ACARS).