An IBM I/O Selectric interface using TTL and a 2708 EPROM

Jay Jaeger cube1 at
Wed Dec 23 08:52:34 CST 2015

On 12/22/2015 10:43 PM, steven at wrote:
> Back in the late 70s early 80s one of Dad's work colleagues came up with this circuit for interfacing
> an IBM I/O Selectric to a microcomputer. We had one, which we planned to use with our Fairchild/Mostek
> F8 development board, but it never got done - my brother and I wanted a computer with a screen, not a
> printer! So we spent our pocket money (and Dad's too) on an S-100 kit system, but that's another story.
> Recently I found the only remains of our I/O writer, the platen. Sadly I think it must have been junked,
> the platen being kept to roll out photographic prints in Dad's darkroom.
> I just finished scanning, cleaning up the degradation and turning the circuit into a PDF. These days an
> Arduino or RasPi would be a simpler and more flexible way to go, but I hope you find it interesting
> looking at how it was done with TTL and discrete components.
> The circuit was designed by (I believe) Neil Taylor, possibly with the help of Derek Williamson, both
> brilliant IBM Australia CE's. I know my dad always spoke very highly of them.
> It's an 8-page PDF at
> Regards,
> Steve Malikoff.

Thanks.  Squirreled away in case I ever find an IO Selectric!


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