Mystery IC: Allen Bradley 314B102

Mike Stein mhs.stein at
Tue Dec 15 16:43:11 CST 2015

----- Original Message ----- 
From: "Mike Ross" <tmfdmike at>
Sent: Tuesday, December 15, 2015 3:41 PM

> On Wed, Dec 16, 2015 at 4:35 AM, tony duell <ard at> wrote:
>> If you can identify the data lines on the connector you are getting there. See if you
>> can trace the other pins to inputs or outputs.
>> -tony
> Tony, good advice but probably more work than I'm inclined to put in.
> As you said there were many interfaces with different standards -
> different polarities and timing - and either way it's quite likely
> this will never work with a standard modern parallel port without
> building some converter, after first finding out what has to be
> converted and designing it!

----- Reply -----

Tony just makes everything sound more complicated than it is ;-) 

Actually I suspect it might indeed quite possibly work with a standard parallel port without any conversion at all other than a rewired cable and maybe a very minor change or two on the board.

For the most part a parallel port is a parallel port; data and strobe going out, strobe acknowledge and printer status coming in, nothing more complicated than that and timing is rarely an issue. In the Selectric there is the R/T code conversion of course but that's done for you already and it should be simple to find the data bit order.

I had a contract years ago that involved adding a serial or parallel interface to Olivetti typewriters and it's really not rocket science; I even still have some info on interfacing to Selectrics but unfortunately not relevant to yours.

Your choice of course but I'd take Brent up on his generous offer to reverse engineer that interface; you may find it's a much simpler project than you think.

(another) mike

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