Robert Weitbrech - and I had to look up his name, though I know the story - is the reason we have, or had (it is a largely obsolete technology now), TTYs in the deaf community.
The exact details of his invention are not known to me, but he took existing teletypewriter technology and brought it into use by deaf people as a means of text communication. ("Not known to me" - teletypewriters existed in some form for use in radio and telegraph comms, but weren't used by deaf people; Weitbrech also developed an innovative acoustic coupler so you could drop a phone handset onto your TTY.)
There's two pieces of this that interest me in a disability+tech context.
One is that this is a collapse of the unfortunate dichotomy of producer vs consumer. I think this is a dichotomy that is resisted in a number of cultures and contexts Project Alloy has ties to - maker culture, hacker culture, FOSS - but there is also a uniquely disability angle to it, in which disabled people are often framed as consumers of tech and of disability tech, and separately from the producers and creators and innovators of tech. (And cue, you know, paternalism and ableism and ... "oh, there are disabled engineers? huh")
The other, and this is the part that feels newer in my head tonight, is the transformative but not normative nature of the TTY.
It is true that one thing the TTY did was grant access to the hearing telephone system. Starting in the mid-70s in the US, you could make a TTY call to a human operator who would then make a phone call, and relay between text and speech. And as of 1997 (Sweden) and 2003 (US), similar services exist for video (ASL or Swedish Sign Language) to speech. Which is great; I can order a pizza, call a potential employer, blah blah. But. TTY (and now videophones) are so much more than that.
They are telecommunications for deaf people. Pre-TTY, if you wanted to talk to a friend, you'd go to their house, and if they weren't home, leave a note on their door. Maybe negotiate a later meetup that way. Or you'd plan on seeing each other at the local deaf club ... at some point. Or if you needed something remote, you could fall back to letters, or asking a hearing friend or relative or neighbor to make a call for you. Imagine, then, pre-Internet, realizing that you could reach out and touch someone (to borrow AT&T's slogan) at a button push! Imagine what that does for a community.
And the reason that excites me is, this is disability tech that is not about normativity, not about trying to live like hearing people, even engage with hearing people [relay service aside]. Nor is it assistive technology, really. It's about what people want to do, and on their own terms, not someone else's. It's about deaf people communicating with each other. (Don't get me wrong - assistive tech is great, I use and love lots of it in my life. This is just something that, while it has applications in assistive tech, is also very separate from it.)