This is incredibly awesome
Also, a bit of #RetroHardware
That's a Panasonic RL-H1400 (not sure of the sub unit coupler). This was capable of multiple attachments, including a thermal printer. Most variants used a 6502 CPU @ 1MHz and 2K - 8K of RAM
Via:
https://www.reddit.com/r/OldSchoolCool/comments/of308i/smoking_gentleman_using_an_acoustic_coupler_to/
@th I was walking past a chair and had to sit down to appreciate the enormity of this image