I got a Voice Modem at some point toward the end of the 90's. I played around with it and wrote an answering machine for it in bash. It announced a synthesized welcome message with date and time, and gave options for control of some elements of my home automation via DTMF (after authenticating). It was clunky, but it worked well.

I came across it a few months ago while clearing out some old junk. I did not think twice about tossing it into the trash.