ARINC 597 : 78 SUPP 5

1.0 INTRODUCTION
1.1 Purpose of this Document
1.2 Airborne Sub-System Configuration
1.2.1 Management Unit (MU)
1.2.2 Control Unit (CU)
1.2.3 Optional additional components
1.3 Interchangeability
1.4 Regulatory Approval
2.0 INTERCHANGEABILITY STANDARDS
2.1 Introduction
2.2 Form Factors, Connectors and Index Pin Coding
2.2.1 Management Unit (MU)
2.2.2 Control Unit (CU)
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
3.0 SYSTEM DESIGN
3.1 General Description
3.1.1 Airborne Sub-System Operation
3.1.2 Radio Frequency Environment
3.2 Message Structure
3.2.1 General Format
3.3 Functional Capability of the Airborne Sub-System
3.4 Labels
3.4.1 System-Essential Labels
3.4.2 Service-Related Labels
3.5 Data Rate
3.6 Encoding and Modulation
3.7 System Timing
3.7.1 Polled Mode
3.7.2 Demand Mode
3.8 Automatic Voice/ACARS Channel Changeover
3.9 Primary Channel Management
3.9.1 Channel Acquisition State
3.9.2 Channel Establishment State
3.9.3 Channel Maintenance State
3.9.4 Uplink Squitter
4.0 UNIT DESIGN
4.1 Management Unit (MU)
4.1.1 Demodulation
4.1.2 Synchronization
4.1.3 Uplink Preamble Processing
4.1.4 Uplink BCS Check
4.1.5 Input/Output Interfaces
4.1.6 GMT Clock
4.1.7 MU Discrete Inputs and Outputs
4.1.8 Downlink Message Formats
4.1.9 Priorities
4.1.10 Polled Mode/Demand Mode Changeover
4.1.11 Downlink Preamble Generation
4.1.12 Downlink Message Assembly
4.1.13 Modulation
4.1.14 Radio Transmitter Keying
4.1.15 Radio Transceiver Tuning
4.1.16 Remaining Downlink Traffic Disposition
4.1.17 MU Interface with Satellite Data Unit
4.2 Control Unit (CU)
4.2.1 Input Facilities
4.2.2 Annunciators
4.2.3 CU-to-MU Data Transfer
4.2.4 Display Provisions
5.0 OPTIONAL AUXILIARY TERMINAL (OAT)
5.1 General
5.2 System Availability to the OAT
5.3 Downlink Message Format
5.3.1 Sequence Number
5.3.2 Flight Number
5.3.3 Ground Addresses and Downlink Priority
        Designation
5.3.4 Text
5.3.5 Block Length
5.4 Downlink Armed
5.5 "No Communications" Alert
5.6 Uplink Message Waiting
5.7 Automatic Data Readouts via the OAT
6.0 OPTIONAL PRINTER
6.1 General
6.2 Form Factor and Connector
6.3 Primary Power Input
6.4 Print Format
6.5 Character Font
6.6 Traffic Consumption Rate
6.7 Buffer Storage
6.8 Accuracy Checking
6.9 Paper
6.10 Functional Test
6.11 Front Panel Controls and Indicators
6.12 Alert Outputs
6.12.1 Alert Output no. 1 (printer busy)
6.12.2 Alert Output no. 2 (priority override)
6.12.3 Alert Reset
6.13 Status Annunciation
6.14 Noise
7.0 PROVISIONS FOR AUTOMATIC TEST EQUIPMENT
7.1 General
7.2 Unit Identification
7.2.1 Pin Allocation
7.3 Use of ATLAS Language
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 Standard Interwiring
        Notes Applicable to the Standard Interwiring
3 Environmental Test Categories
4 Command/Response Message Text Formats
5 Standard Seven-Unit Code
6 Encoded Sub-Carrier Waveform
7 Voice/ACARS RF Channel Changeover
8 Serial Digital Channel Selection
9 Mode Character Definition
10 Channel Selection Algorithms
APPENDICES
1 HF ACARS System Description & Link Operational
        considerations
        HF ACARS Avionics Block Diagram
2 Chronology and Bibliography
3 OAT design "A"

Covers the airborne components of the ARINC Automatic Communications Addressing and Reporting System (ACARS). The system is meant to be used in conjunction with existing airborne radio equipment to improve the effectiveness of air ground operational control communications. This improvement accrues from the abilities of the system to give ground to air and air to ground signaling as well as as air to ground and, in an expanded form, ground to air digital communications.