Bob Rosenbloom wrote: The IBM MAG card Selectric's are not too hard to find. Their not cheap, about $50 each, but I've found two in the last year. I have not tried to interface one yet but I do have the manuals and don't think it would be too hard. Also, they made a "Communications MAG Card Typewriter" that has some sort of interface on it. I just missed one a few months ago. Another thing to look out for is the military I/O Selectric's. I bought two from govliquidation a few years ago. Both have some damage from poor shipping though. These have a big round military (ITT/Cannon) type connector and I have yet to find any info on them. I was lucky to find them, they were listed as "Human Communication Device, Typewriter"! My real quest is a "Model B" I/O typewriter as was used on the IBM 1620, model 1. Probably end up with a bunch of solenoids under a standard typewriter! Bob ----------------- Billy responds: I consider $50 for a Selectric with interface connections extremely cheap. I would expect them to be much more scarce than that. The military machines sound familiar. I'm certain they are covered in some manuals I loaned Al recently to scan. The heart of the I/O Writers used the IBM model 72 and model 73. Al has my manuals for both - they are CDC reprints of IBM Service manuals. Plus I loaned him some parts manuals that have great exploded views for repairing the units. I used all of these manuals when I was trained on the Selectrics, back in 1967. Also, Al has already posted some IBM reference manuals. But I think they are in the CDC folder under terminals. One of the manuals I loaned Al also has all the interface timing and signal levels and how to control. Finally, Wayne Green published a nice little paperback on interfacing a Duramachine to a PC. It has a good basic circuit that could be used to start your own design. I have one Model B with the Sorobon mechanism to drive the typewriter from a computer. It was used on all the CDC computers plus many of the other computer companies of the era. I don't believe that IBM used Sorobon, instead did their own design on the 1620. But I've never dug into a 1620 so don't know what the encoder looks like. I have some other Model B's to use as spares, but no other encoding devices. Would love to find more on the history of that company: Sorobon. About all I know is that they were based in Florida when I ordered some parts from them in the 70's. Still have some of the spare solenoids they used. Guess I should measure and document them. Billy