: You can find unclassified catalogue summaries on platforms like Technical Context : Research papers on ResearchGate
(13 digits, often written with hyphens)
This led to the development of the messages (e.g., M-1, M-2, etc.), which were character-based message texts defined in APP-11. These were designed for low-bandwidth environments, where every character transmitted over high-frequency radio waves counted. The APP-11 PDF of this era contained strict columns and field definitions—a "fill in the blank" approach to warfighting data. nato app-11 pdf