Archived from groups: alt.comp.periphs.mainboard.asus (
More info?)
In article <xgmXe.2039$yN1.1212@trnddc03>, Wayne <nospam@invalid.com> wrote:
> News just in...
>
> It has been explained to me that I am confusing the wiring.
>
> I was wrong, and the wiring on the internal COM2 cable that I have is
> NOT Straight-through. It is instead crossed, and it doesnt work on the AV8
> Deluxe. I obviously need a straight-through cable, in agreement with
> conventional wisdom for Asus (but not tested yet).
>
> The crossed cable I bought didnt specify what it was (most dont), but after
> opening the hood, the pinout of a cross-wired cable matches the actual
> ordering of the DB9 pin arrangement, and the final result of a crossed cable
> allows the ribbon to remain very flat and very orderly after wiring each
> consecutive ribbon wire to the next closest pin, left to right, simply
> ALTERNATING UPPER AND LOWER PIN ROWS in the same order as the ribbon cable.
>
> This must be the only purpose of the crossed function, since extension
> cables are otherwise always straight through. I superficially confused this
> orderly straight wiring with a straight-through cable, but it is instead a
> crosswired cable, designed to be very flat and orderly at the DB9.
>
> A straight-through cable wiring is much more jumbled up at the DB9, having
> to loop back to several pins on the other side, due to the DB9 pin numbering
> scheme itself being jumbled, at least in any left-to-right sense like say a
> ribbon cable is orderly.
>
> I hope this can help someone else now, instead of confuse.
"ALTERNATING UPPER AND LOWER PIN ROWS" - I think that is DTK.
I realize after thinking about it some more, that my cable
description terminology leaves a lot to be desired. "Crossed"
seems to lack precision
My reference point in a cable assembly like this, is the
ribbon cable. The wires in the ribbon cable start with wire 1
being the one marked with some red color on the insulation.
The end of the ribbon cable assembly that plugs into the
motherboard, is an "insulation displacement technology" or
IDT connector. No solder is used - instead each wire is pushed
between two tiny posts, and the posts bites the wire. The
insulation on each wire is displaced. (This is the same method
used to make PATA (IDE) cables.) It has a 2x5 hole pattern,
with 0.1" spacing grid for the holes. When the linearly numbered
ribbon cable wires are connected to the IDT connector, the connector
pin numbering looks like this.
(when ribbon is compressed against a 2x5 header and
the other end is compressed against an IDT DB-9.
This is apparently DTK wiring pattern - not Asus)
1 3 5 7 9 12345678910 1 3 5 7 9
2 4 6 8 10 (ribbon cable) 2 4 6 8
ribbon number ribbon number
where it hits 2x5 where it hits DB-9 pin
In the above, if a DB-9 connector that uses IDT on its
backside, is connected to a ribbon cable, the wires go
to the nearest pin as you move left to right. This is,
apparently, the DTK wiring pattern. To using this crimping (mass
termination) method, the ribbon cable cannot randomly select
any pin on the connector at the other end. In North America,
this would be the cheapest way to make a cable, and would be
preferred from an assembly cost perspective.
With the DTK assembly, the ribbon cable on either end should
come out the "side" of the connector (that is how cables
made with IDT method work). A side view of a DTK
cable should look like this:
|X X| 2x5 \|X X|/ DB-9
| | | |
--------------------------------- side view DTK
[___] [___]
To make any other wiring pattern, requires a DB-9 connector with
solder terminations sticking out the back of the connector.
In the AT-Everex-Intel wiring, the 2x5 end of the cable is still
fastened by the IDT method. But, at the DB-9 end, the first
five sequential wires of the ribbon, are soldered to the top row
of DB-9 solder terminals. The next four sequential wires are
soldered to the bottom four terminals. The DB-9 shield ground
is established when the PCI bracket is screwed to the computer
chassis. Again, using only the "ribbon cable number" as the
reference numbering scheme, an Everex cable looks like this
(Asus style).
(when ribbon is compressed against a 2x5 header and
the other end is soldered to a soldertail DB-9.
This is apparently Everex wiring pattern used by Asus,
at least that is frontx.com's claim.)
1 3 5 7 9 12345678910 1 2 3 4 5
2 4 6 8 10 (ribbon cable) 6 7 8 9
ribbon number ribbon number as soldered
where it hits 2x5 to DB-9 pins
With the Everex assembly, and the need to solder the wires to
the DB-9, it is possible the wire on the DB-9 end, will come
out the end of the assembly, like this.
|X X| 2x5 \|X X|/ DB-9
| | | |
--------------------- | | side view Everex/Asus
[___] \ [___]
\ / <-- wire on end
\______/
Now, everyone knows that there are numbers printed next to
each pin, when looking into the end of a DB-9 connector.
The numbers you see printed on the end look like this, and
you'll need a magnifying glass to see them.
1 2 3 4 5
6 7 8 9
Those are the numbers you will see if consulting internet pinout
web pages, for example when wiring up null modem cables and the
like. I will switch to using those numbers in the "wiring
tables" below.
Now, a couple of web page examples.
**************************************************
This page sells an Everex/Asus cable. The information shown is
a "wiring table", in "from-to" format.
http://www.pccables.com/07120.htm
(Picture of how it is soldered - frontx V1 "Asus" cable
First five wires to top, next four wires to bottom)
http://www.frontx.com/cpx102_2_p4.gif
__________
/ \
| first five wires in ribbon
v to top row
-------------- | -----------
\ 1 2 3 4 5 / 12345 | 1 3 5 7 9 | Everex/Asus
\ 6 7 8 9 / 6789x | 2 4 6 8 x |
---------- | -----------
^ next four wires
| to bottom row
\________/
From DB-9 pin 1 to Header pin 1
From DB-9 pin 2 to Header pin 2
From DB-9 pin 3 to Header pin 3
From DB-9 pin 4 to Header pin 4
From DB-9 pin 5 to Header pin 5
From DB-9 pin 6 to Header pin 6
From DB-9 pin 7 to Header pin 7
From DB-9 pin 8 to Header pin 8
From DB-9 pin 9 to Header pin 9
**************************************************
This page sells a DTK cable (the one we don't want).
http://www.pccables.com/07121.htm
(Picture of how it is soldered - frontx V2 "non-Asus" cable
ALTERNATING up-down pattern)
http://www.frontx.com/cpx102_2b_p4.gif
Ribbon cable wire - wire 1 goes to pin 1, wire 2 goes to pin 6
| wire 3 goes to pin 2, wire 4 goes to pin 7.
| A natural for IDT press fit installation
| and side mounted cable exit, but could
v still be made by end-on soldering as labor
in Taiwan is cheap.
123456789
|||||||||
vvvvvvvvv
-------------- -----------
\ 1 2 3 4 5 / | 1 3 5 7 9 | DTK
\ 6 7 8 9 / | 2 4 6 8 x |
---------- -----------
From DB-9 pin 1 to Header pin 1
From DB-9 pin 2 to Header pin 3
From DB-9 pin 3 to Header pin 5
From DB-9 pin 4 to Header pin 7
From DB-9 pin 5 to Header pin 9
From DB-9 pin 6 to Header pin 2
From DB-9 pin 7 to Header pin 4
From DB-9 pin 8 to Header pin 6
From DB-9 pin 9 to Header pin 8
**************************************************
I haven't used the word "crossed" in this attempt, so
maybe this attempt will be clearer.
Refs:
http://home.att.net/~Tom.Horsley/p4c800e.html (Everex by experiment)
(Near very bottom of page "COMM & LPT" - shows an Everex wire table)
http://web.archive.org/web/20040604064344/http://www.jump.net/~lcs/kalle/rev3.htm
http://www.frontx.com/cpx102_2.html (Asus)
http://www.frontx.com/cpx102_2b.html (non-Asus)
Paul
Facebook
Twitter
Instagram