My one cousin is mostly deaf and had something similar hooked up to their phone while he was growing up from the phone company I believe. I'm sure the operator had a fair amount of amusement from his conversations being the go-between.

Both of my parents were deaf. Growing up in the (pre texting and Skype) 70's my parents and most deaf folks used government surplus teletype machines communicate with friends and family on the phone. I didn't know of anyone in my parents circle who didn't have one. Every one knew of someone who squirreled away parts for these loud, rumbly and gigantic beasts who repaired them in the basement . Are these things the same machines? They look much smaller than i remember.