1.0 AIR/GROUND COMMUNICATION
1.1 Introduction
1.2 Purpose of this Document
1.3 Document Organization
1.4 ACARS System Description
1.5 ACARS Components
1.6 ACARS Messages
1.7 Relationship to Other Documents
1.8 Documents Referenced
2.0 AIR/GROUND BLOCK STRUCTURE
2.1 General Format Description
2.2 Downlink Block Format
2.3 Uplink Block Format
3.0 ACARS MESSAGE PROTOCOL
3.1 Basic Message Protocol
3.2 Acknowledgment Protocols
3.3 Message Addressing
3.4 Message Sequencing
3.5 Retransmissions
3.6 Multi-block Processing
3.7 Unable to Handle Uplink
3.8 Message Prioritization
4.0 VHF ACARS
4.1 Radio Frequency Environment
4.2 VHF Preamble
4.3 BCS Suffix
4.4 Modem Interface
4.5 Medium Access Control
4.6 Transceiver Control
5.0 VHF LINK MANAGEMENT
5.1 Functional Capability of the Airborne Subsystem
5.2 Permission to Send
5.3 No VHF Communications (NO COMM)
5.4 Timers and Counters
5.5 Retransmission Logic
5.6 Frequency Management
5.7 Operation on Alternate Frequencies
5.8 Category A Network Operation
5.9 Category B Network Operation
5.10 Statistical Data Collection and Reporting
5.11 Transit Times
6.0 VOICE MODE OPERATION
6.1 Introduction
6.2 Manual Channel Changes (VOICE/DATA)
6.3 Automatic Channel Changes (VOICE/DATA)
6.4 Configuration Programming Functions
6.5 AOC Voice Channel Signaling
6.6 VOICE Mode Advisories to the Crew
6.7 VOICE Mode Advisories to the DSP
6.8 Mode Transition Logic
7.0 SATCOM INTERFACE
7.1 Overview
7.2 Data Bus Interface
7.3 Command and Control Interface
7.4 Link Interface
7.5 ACARS Message Protocol
7.6 Satcom Link Management
7.7 Media Utilization
8.0 HF INTERFACE
8.1 Overview
8.2 Data Bus Interface
8.3 Command and Control Interface
8.4 Link Interface
8.5 ACARS Message Protocol
8.6 HF Link Management
8.7 Timers and Counters
8.8 Media Utilization
9.0 MEDIA UTILIZATION
9.1 Overview
9.2 ACARS Satellite Datalink
9.3 ACARS HF Datalink
9.4 ACARS Using VDL Mode 2 Datalink
10.0 CMU OPERATION WITH VDR OPERATING IN VDL MODE A
10.1 Overview
10.2 Data Bus Interface
10.3 Command and Control Interface
10.4 Link Interface
10.5 ACARS Message Protocol
10.6 VDR Link Management
10.7 Media Utilization
10.8 Voice/Data Switching
11.0 ACARS OVER AVLC
11.1 Concept
11.2 CMU/VDR Interface Overview
11.3 ACARS Message Protocol
11.4 AOA Link Management Timers
11.5 Switching Between ACARS and AOA
1.6 ACARS VHF Manager
11.7 AVLC Requirements
ATTACHMENTS
ATTACHMENT 1 - AIR/GROUND COMMUNICATIONS
ATTACHMENT 2 - FREQUENCY MANAGEMENT
                DIAGRAMS
ATTACHMENT 3 - ISO 5 CHARACTERS
ATTACHMENT 4 - MULTI-BLOCK TIMING
                DIAGRAMS
ATTACHMENT 5 - MSK WAVEFORMS
ATTACHMENT 6 - MODE CHARACTER
ATTACHMENT 7 - VOICE/DATA NOTIFICATION
ATTACHMENT 8 - DATA RECORD CONTENTS AND
                FORMAT
ATTACHMENT 9 - MEDIA ADVISORY LOGIC
ATTACHMENT 10 - MESSAGE SEQUENCE CHARTS FOR
                DOWNLINK ACKNOWLEDGMENT ON
                SATCOM/HFDL
ATTACHMENT 11 - MESSAGE SEQUENCE CHARTS FOR
                UPLINK ACKNOWLEDGMENT ON
                SATCOM/HFDL
ATTACHMENT 12 - NESTED MULTIBLOCK TIMING
                DIAGRAMS
ATTACHMENT 13 - MU-VDR PROTOCOL NEGOTIATION
                MESSAGE SEQUENCE CHART
                EXAMPLES
ATTACHMENT 14 - PROPAGATION DELAY
ATTACHMENT 15 - GENERAL FORMAT OF AIR/GROUND
                DOWNLINK AND UPLINK MESSAGES
ATTACHMENT 16 - AOA PROTOCOL ARCHITECTURE
ATTACHMENT 17 - AVLC FRAME STRUCTURE
ATTACHMENT 18 - AOA MESSAGE SEQUENCE CHARTS
                AND FLOW DIAGRAMS
ATTACHMENT 19 - AOA TIMING DIAGRAMS
APPENDICES
APPENDIX A - PROTOCOL HISTORY
APPENDIX B - A CARS OVERVIEW
APPENDIX C - INSTALLATION TEST GUIDANCE
APPENDIX D - SATELLITE CATEGORY B
APPENDIX E - VDL MODE 2 TIMING BUDGET
APPENDIX F - TERMS AND ACRONYMS