hilpert at cs.ubc.ca
Sun Nov 15 18:56:14 CST 2009
Philipp Hachtmann wrote:
> Hi folks,
> I don't know if it's a fact of certain interest...
> I found a DEC M841 Omnibus printer interface with a Fairchild "F 7429DC"
> additionally stamped "DEC8881". As I think the DEC8881 is considered one
> of the harder to find chips, this could be interesting. I know that many
> of the DECxxx ICs are pin compatible to standard 74 TTL or Signetics 82
> TTL devices so this could be found out by reading the TI data book as
> well. But I've heard of signal quality, speed and other selection issues
> making those a DECxxx IC. Perhaps that's a legend? Or at least partially?
> Best wishes,
> Philipp :-)
> p.S.: Here's a picture: http://pdp8.hachti.de?gallery/misc
(Found the picture at: http://pdp8.hachti.de/?gallery/misc
7439 as Chuck said.)
I find the 7439 in only the Fairchild books, doesn't appear in the TI or
National books I have.
One Fairchild book lists it as a line driver along with the Fairchild 96101
(9600 series: same pinout and drive capability, some diffs in the way the specs
are presented). One line of speculation would be that DEC originally chose the
96101, internally named it the 8881, then Fairchild phased out the 9600 series
as 7400 took over, but DEC needed to keep that chip going.
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