25 Aug
2014
25 Aug
'14
3:33 a.m.
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
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
25 Aug
25 Aug
3:41 a.m.
On Mon, Aug 25, 2014 at 1:33 AM, David Griffith <dgriffi at cs.csubak.edu> wrote:
While I'm prepping parts for P112 kits, I started
thinking about DE-9
pigtails. These things come in two different pinouts.
I've used dozens of those over the years, and I've only ever seen the ones
that use straight-through ribbon cable (interleaved pinout). I've never seen
the other kind you mentioned, with the split ribbon cable.
5:29 a.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of David Griffith
Sent: 25 August 2014 08:33
To: cctalk at classiccmp.org
Subject: DE9 pigtail pinouts
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.
I bought some recently for my SBC6120 and they didn't seem to follow either
pattern. Had me stumped for ages. They were StarTech
http://www.ebay.com/itm/161384378523
Its possible older designs assumed that you had IDC both ends, so an IDC
DE-9. Because of the way a 9-pin is numbered results in an interleaved
layout when you write it down...
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
1:22 p.m.
On Mon, Aug 25, 2014 at 3:29 AM, Dave G4UGM <dave.g4ugm at gmail.com> wrote:
I bought some recently for my SBC6120 and they
didn't seem to follow either
pattern. Had me stumped for ages. They were StarTech
http://www.ebay.com/itm/161384378523
Its possible older designs assumed that you had IDC both ends, so an IDC
DE-9. Because of the way a 9-pin is numbered results in an interleaved
layout when you write it down...
That's the only kind I've ever found, and what I thought David was referring
to by the "interleaved" configuration.
4:05 p.m.
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.
I've only ever seen the ones you call 'interleaved'. Actually, I rarely
buy such things, I make my own, If you use IDC DE9 connectors you get the
interleaved pinout. And if you solder the DE9 end I find it easier to
interleave the wires (split the cable between each wire, fold back the
even numbered wires. solder the odd-numbered wires to the row of 5 pins,
athen turn the conenctor roudn and solder teh even numbered wires to the
row of 4 pins) than to sodler the first 5 wires to the row of 5 pins then
take the remaing 4 wiires from teh side of the bakc back to the conenctor
and solder them to the wor of 4 pin.
So I would certianly stick with the interleaved pinout.
-tony
7:30 p.m.
On Mon, 25 Aug 2014, David Griffith wrote:
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.
I've seen PCB pin headers for serial ports using three kinds of wiring. I
think whoever makes/sells these pigtails should state the wiring as
there's no single established standard. I saw two different ways with x86
PC-class computers where, reportedly at the time I had to fiddle with this
stuff (late 1990s/early 2000s), most PC equipment manufacturers used one
way but Tyan used their own (no pin assignment reference at hand, but I
presume the common one was the two-section version you've described and
the Tyan one was something exotic; they later switched to the common one
I'm told).
Yet when I got to wiring a serial port pin header on a MIPS development
board I got, none of the pigtails I had was right and I had to rewire one
(I used a DB-25 rather than DE-9 connector actually as that was what I
needed). And looking at the board schematics it was one you refer to as
"interleaved":
1->CD
2->DSR
3->RX
4->RTS
5->TX
6->CTS
7->DTR
8->RI
9->GND
10->N/C
So I think your observation is right, the two-section version is probably
more common, which is why you can get correct pigtails for it more easily.
Maciej
3617
days inactive
3617
days old
5 comments
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participants (5)
-
ard＠p850ug1.demon.co.uk -
dave.g4ugm＠gmail.com -
dgriffi＠cs.csubak.edu -
macro＠linux-mips.org -
spacewar＠gmail.com