That sounds like the Internet Relay used by handicapped to communicate. The calls were subsidized by U.S. taxpayers.
Deaf person types message to an operator who communicates by voice with hearing enabled person. Takes forever and costs a fortune in operator time.
At best the program was highly questionable. Then things got much worse.Scammers started using it a few years ago. They'd sit in a internet cafe in Nigeria and have operators phone U.S. businesses one after another trying to get them to send Ipods and Nikes to Lagos. The calls were utterly free to the Nigerians and the caller didn't even have to know much English. Furthermore the operators are sworn to secrecy.
If the recipient asks whether the call is a scam, the operator isn't allowed to comment in any way! Some relay operators spend their days relaying one scam attempt after another.
Here, try it yourself! You don't have to be deaf. Use it to make prank calls. Order a pizza. Heck, call Rome and order a pizza. No extra charge for international calls. Sure it costs SOMEONE a fortune. But not you (at least directly)
https://www.sprintip.com/index.jspps: don't threaten to kill someone. That is about the ONLY limit to this ridiculous government program.