Yes, FPL messages are sent over AFTN, which uses ITA-2 Baudot code instead of ASCII: https://en.wikipedia.org/wiki/Baudot_code https://en.wikipedia.org/wiki/Bau

Yes, FPL messages are sent over AFTN, which uses ITA-2 Baudot code instead of ASCII: https://en.wikipedia.org/wiki/Baudot_code https://en.wikipedia.org/wiki/Baudot_code The keyboards used by ATC don't even allow entering symbols: https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2F1ktpo3pi4th21.jpg https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2F1... (There is a modern replacement for AFTN called AMHS, which replaces analog phone lines with X.400 messages over IP... but the system still needs to be backwards compatible for ATC units still using analog links.)