Glass:
Not sure if this will be helpful in your search for code, but the vt-100 terminal was, itself, an emulation of the ASR-33 Teletype.
Well, the Model 33 ASR Teletype was one of the first serial terminals to send/receive ASCII, but given it was a machine that wrote to paper and/or punch tape, and read from the keyboard or punch tape, and the VT-100 was a cathode ray tube with 80x24 characters (or 132x14 or optionally 132x24) on the screen, and it had escape characters for bold, underline, character position, etc.
But I'm not sure I would call it emulation. Certainly if it was going to emulate the Teletype, it would need a paper tape reader/punch (I used to get paper cuts a lot handing paper/mylar tape). To be a full emulation, the VT-100 would also with a speaker to simulate the sounds. since the Teletypes were always noisy. Except for the bell, the only time the character terminals made noise was when the flyback transformer was starting to go, and we would do some percusive maintainance (i.e. hit it to realign things).
Evidently calling the Teletype ASR-33 came from a DEC manual, and it wasn't the official teletype model: