Yep, the IBM 3174 terminal controller Asynchronous Emulation Adapter or feature allowed you to connect ASCII terminals to a mainframe host and allowed 3270 devi

Yep, the IBM 3174 terminal controller Asynchronous Emulation Adapter or feature allowed you to connect ASCII terminals to a mainframe host and allowed 3270 devices to connect to an ASCII host. There were options from other companies in those days too. Later, with LAN connectivity, there was quite a bit of bridging different technologies you could do with a 3174.