Incompatible Baudot FSK machine has great TTY line editor (Patreon)

I have recently collected 3 semi-modern (1970s to 1990s) Baudot FSK machines. They are basically teletypes equipped with a frequency shift keying two-tone modem. The idea is to have a pseudo modern RTTY (radio-teletype) test setup before I try to do it the original way with technology from the 1940's and 1950's, with tubes of course. 

They each have their own retro display method: the 3M Telex uses a thermal TTY printer (1970s), the Japanese TONO writes on a CRT (1980s), and the Ultracom has an alphanumeric green VFD (1990s).

However, unbeknownst to me, although they all use low rate Baudot and FSK modulation, they are all incompatible! They all use different FSK base frequencies and shifts! What the?

But the 1970s Telex machine has an unexpected capability: a built-in single line editor that can edit up to 4 kB of text before sending it. And it is surprisingly easy and efficient to use. Who would have known: you can actually make an intuitive TTY single line editor using a printer "display". I'm suitably impressed.

Marc