Early 72-pin bus for 8080?

[roger arrick]

Does anyone recognize this 72-pin bus on .156 centers from back in the 8080 era, mid-70s?

I've always thought it was a random proprietary design but maybe it was modeled after something in intel databooks.

--  Roger Arrick -- Tyler, Texas, USA -- Ro...@Arrick.com --

[Herbert Johnson]

On 12/30/2024 2:02 PM, roger arrick wrote:
> Does anyone recognize this 72-pin bus on .156 centers from back in the
> 8080 era, mid-70s?
>
> I've always thought it was a random proprietary design but maybe it was
> modeled after something in intel databooks.
>
> --  Roger Arrick

+10V +20V -20V, S-100 as a common bus used unregulated power lines, but
unregulated in the 1970's was not unusual. Otherwise it's 8 bit data, 16
bit address, some 8-bit R-channel or maybe interrupts. The AEN signal
suggests an 8085/88 processor as does the I/O read and write signals. I
can't quite read the CPU chip in the photo.

There were many industrial controllers in the era, also commercial
product with bussed boards. Haunt eBay long enough and you may see
another industrial board with this connector and with DC power doubled
up on pins far from the ends of the connectors. Lots of current
capability suggests an application that drew power, like a printer or a
motor driver and so on.

regards Herb

--
Herb Johnson, New Jersey USA
http://www.retrotechnology.com or .net
preserve and restore 1970's personal computing
email: hjohnson @ retrotechnology dot com
or try later at herbjohnson @ comcast dot net