Puzzle Codes

Braille (uncontracted Unified English Braille, as cells or dot numbers), flag semaphore, the International Code of Signals flags, the NATO spelling alphabet, tap code with its sound, and phone keypad codes, each both ways where the code allows. ICAO adopted the spelling alphabet in 1951 and its present words in 1956; tap code is the square Polybius describes (Histories X.45), knocked row then column.

• International Council on English Braille, Unified English Braille and Rules of Unified English Braille (third edition, 2024)
• National Geospatial-Intelligence Agency, Pub. 102, International Code of Signals
• ICAO, Uniting Aviation, “As easy as Alfa Bravo Charlie”
• Polybius, Histories X.45–46, trans. W. R. Paton (Loeb Classical Library, 1925), LacusCurtius
• Recommendation ITU-T E.161, Arrangement of digits, letters and symbols on telephones (2001)