I’ve written an experimental TTY/TDD (45.45 baud, 5bit baudot, 1400/1800 Hz) telnet RAS interface for yate. It’s integrated into my RAS project (uses the same telnet, yate interfacing logic, codec handling, etc.).
For modulation, I’m calling:
which handles the FSK for me.
Minimodem can also handle “Bell103, Bell202, RTTY, NOAA SAME” as other modulations, so having a generalised minimodem interface is probably useful anyways.
I’ve configured it as a new service, just sending out the current time every 5 seconds:
TTY/TDD test line
Time announcement (45.45 baud, 5bit baudot, 1400/1800 Hz)
I’m sure there are way more fun uses for this (ZORK1 over TTY? Wikipedia? Fediverse?).
Service ideas welcome, they just need to be a Linux program or Telnet service.
It brings me to the question: Does any of us have any actual hardware equipment that can process this data? I’ve always read about this TDD technology, but never saw any actual commercially available device/implementation of it. Sure, one can do it in software, but to me that’s really only half of the fun. If both ends are some modern software implementations, it doesn’t really have the kind of hands-on retronetworking appeal…
Thanks for your enthusiasm working on that kind of stuff (and for your updates here!).
p.s.: typing test… Reminds me of the DOS shareware I wrote in 7th grade (1992/1993), which was a 10-finger-typing training program that looked like an ANSI BBS (graphics drawn with TheDraw) which played MOD files in the background while you were learning how to type. I think I might still have the TurboPascal sources for that somewhere