I used to take home a terminal from work in the mid 70s. Same principle but portable. It had two rubber cups which the two ends of the phone would push into and after dialing up I was ready to go.
I had one of those, dunno what happened to it...fun story, I was living in Boston at the time, and there was too much line noise on the phone system for 300 baud, but 110 baud worked like a charm.