"Minitel use peaked in 1993". The closest technology at that time outside France would have been bulletin board services (BBS). Each was run as a separate walled garden but many were linked by Fidonet. So not too dissimilar to Minitel, just more diverse and decentralized.
There was a similar system for minitel: these were called RTC servers. Nothing to do with WebRTC.
It was short for Réseau téléphonique commuté. Basically a simple user would run the equivalent of bbs software on his computer, but with specific tweak that it could talk in videotex encoding.
And then of course he would use a modem (even in hackish ways the modem of an existing Minitel) to answer calls on a normal phone line (no x25 here).
