While I'm prepping parts for P112 kits, I started thinking about DE-9
pigtails. These things come in two different pinouts. One of them is
pin-1 of the header connects to pin-1 on the DE-9. When wiring up a
pigtail like this manually, you cut the ribbon cable into two sections.
One sections goes on the top row of the DE-9. The other section goes on
the bottom. The other one has the pins interleaved. See
http://661.org/p112/files/pigtail.pdf for what I mean.
The P112 was designed with the second pinout in mind. When I bought
pigtails for my first run of P112s, I managed to get that kind. For
subsequent runs, I always got the first kind. Which pinout is more common
with actual devices? I ask this because I'm tinkering with an amateur
radio project that will eventually use DE-9 pigtails.
--
David Griffith
dgriffi at
cs.csubak.edu
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