Mystery IC: Allen Bradley 314B102

There were just about as many parallel interface versions as devices that used them back then..... Nothing 'common' really... The idea of 7 or 8 data lines, a strobe, and a ready signal was certainly arround back then, but the timing, polarity (active high or low) and timing were not standardised. A couple of examples that I can see without getting up are the Facit 4070 paper tape punch and the HP9866A thermal printer. Those were both around in the early-mid 1970s and are rather different parallel interface. OK, what I would do to get some idea is focus on those 7475 chips. Get the pinout. The most obvious use for them on this board is as the character input latch. IIRC each is really 2 2-bit latches, so 2 enable/clock pins on each chip. So : 1) Are the 4 clock pins linked together (if so, it loads a character at a time [1]), or are they in pairs or what 2) Where do the D inputs go? Are any of them linked together, or do 7 or 8 of them go to the interface connector? If the latter, then those are the data inputs. [1] Before anyone suggests you could use them as a sort-of shift register and load half a character into one, then copy it into the second one while loading the other half character, remember the 7475 is a transparent latch, not an edge-triggered flip-flop making this a very difficult thing to do. 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