I used a later derivative of this concept to produce a book while at university. It consisted of a Selectric typewriter with a solenoid-driven interface which c

I used a later derivative of this concept to produce a book while at university. It consisted of a Selectric typewriter with a solenoid-driven interface which connected to a metal box containing a compact cassette mechanism and a few buttons. Type a line, make corrections and hit the carriage return key upon which the result is stored on cassette tape. Recorded lines could be edited, ed-style by replacing sections (characters or words) with new content. Once stored the thing could be used to produce many copies of the same content with pauses for manually typing in addresses etc. I used it to produce a whole book during which the typewriter motor died just after having typed in the whole thing and just before I was going to have it 'print' the text so we could cut and paste it on stand sheets for offset reproduction. I managed to find a working motor which I installed in the machine upon which I had to re-adjust the whippletree mechanism which aims the ball since the characters ended up everywhere except for where they needed to be. Those were a few intense hours since I had to go by intuition on how this all worked, not having access to a service manual and this being long before the time when you'd just go on the 'net to find one. I got it adjusted and got the book printed by feeding the typewriter with paper and the device with cassette tapes, telling it to print a page, feeding in a new sheet, next page, next cassette tape, etc.