I used a more primitive device also made by IBM. I would type a line blind and when I had entered a set number of characters, the device would print out a line right and left justified. These would be pasted up on a copy board and then photographed. The resulting negative would be mounted on a flat specific to the press that was going to print the work, touched up for any imperfections and then used to burn a plate. It seems impossibly primitive now.
Yikes!! That sounds a lot less efficient than linotype, even.