Using an Old Book Chart Blindly
Check whether it is labelled American Morse.
Clear comparison of American landline Morse vs International Morse — and which one to learn.
Direct answer: American Morse was landline telegraph code with different patterns/timing for some letters. International Morse is the global radio/ITU standard — what this website uses exclusively.
| American Morse | International Morse | |
|---|---|---|
| Era / use | 19th-c. US landlines | Wireless / modern CW / apps |
| Interoperability | Regional historical | Worldwide standard |
| This site | Not used | Used for all tools/charts |
Learn International Morse unless you are studying historical telegraph specifically. Licence courses, ham CW, and modern converters assume International patterns.
Full International tables: International Morse page. History context: history.
Wrong-chart errors create silent decode failures.
Check whether it is labelled American Morse.
Pick International and verify decode.
Always specify International for radio/web use.