18 Apr
2019
18 Apr
'19
12:34 p.m.
On 2019-Apr-18, at 8:47 AM, Jon Elson wrote:
On 04/18/2019 04:49 AM, Brent Hilpert via cctalk
wrote:
Well, not everybody - I have a 4-wire, diagonal-sense module with IC date codes extending
from 1974 to 1978.
Certainly it's an outlier, on the tail-end of the distribution curve of production of
such design,
but that's why I expressed dating it to the 60s as a likelihood, not an absolute
surety.
(The ICs are 711 comparators and diode arrays. The 711 does go back to at least 1969 so
it's conceivable
the design of the module goes back to the late 60s, although that's seems less likely
considering production into 1978.)
It's a 4-wire 3D planar array. By topology
and construction I would guess it date it from the 60s.
Make that EARLY '60s.
As soon as somebody figured out that you could combine the sense and inhibit wires,
everybody immediately went to 3-wire planes.