M17 Project is a modern, digital radio protocol built by hams, for hams. This repository contains the specification describing it exhaustively, from top to bottom. It is still a work in progress, meaning that this repository is meant to be updated now and then. After a few years of development, almost all of the changes are just to supplement the specification with new functions or improve the document.

The specification can be conveniently browsed here.

Part I - Air Interface

• M17 RF Protocol: Summary
• Glossary
• Physical Layer
  • 4FSK generation
    • Preamble
    • Bit types
    • Error correction coding schemes and bit type conversion
• Data Link Layer
  • Stream Mode
  • Packet Mode
  • BERT Mode
• Application Layer
  • Amateur Radio Voice Application
  • Packet Application

Part II - Internet Interface

• M17 Internet Protocol (IP) Networking
  • Standard IP Framing
  • Control Packets

Appendix

• Address Encoding
  • Callsign Encoding: base40
  • Callsign Formats
• Randomizer sequence
• Convolutional Encoder
• Golay Encoder
• Code Puncturing
• Interleaving
• BERT Details
• KISS Protocol
  • References
  • Glossary
  • M17 Protocols
  • KISS Basics
  • Packet Protocols
  • Stream Protocol
  • Mixing Modes
  • Implementation Details
• File Formats