I know it is a long shoot ! The IBM 6715 / Actionwriter was one of the last daizy wheel typewriter made by IBM Germany. ( said to be made to last at least half century, German design ;-) )
It has "kind" of a RS232 port on the back, I was unable to find any information on this port which was intended to support two "extremely rare" !!! IBM options one beeing a REAL RS232 port, the other some kind of display of the two last line typed. I wonder if someone has even connected this typewriter to a computer. It would be fun to use it like a "modern" TTY but I think the problem is probably that this typewriter expect a "lot of" (??) proprietary commands to set type spacing, margins, baud rate etc .... Any advice ?? Any help ??