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header for serial?

D

dbarton

Senior member

My ASUS MB has a pins on the mobo for a serial port, but no back plate connector. I had one in my shed from years ago, but I heard they may have changed the pinout on newer machines.

That make any sense to anyone?
Windows say serial port is working, but it isn't..

If so, where does one get the right one?
(and one for USB too)
 
You can use a multimeter to check the pinout of your cable. The IDC10 plug on the end of the flat cable has this pinout:

2-1
4-3
6-5=
8-7
10-9

The = is the key. Pin 10 isn't used since this serial is a 9 pin. So, 1 goes to pin 1 on the serial port. 3 goes to pin 2. 5 goes to pin 3 and so on.

1=1
3=2
5=3
7=4
9=5
2=6
4=7
6=8
8=9
 

It's a little hard to follow the diagram above, but I'm gonna try. I see the key so I see here pin one woudl be on the square end, but hwioch is pin1 on db9 end?

Is there any truth to the mention that there was one pin out style for old headers, and a new style now, so mine may just be outdated? Seems odd they'd change like that.
 
Originally posted by: Fallen Kell
http://www.lammertbies.nl/comm/cable/RS-232.html

Has some pictures of the pins numbers so you can figure them out a little better...
Click to expand...

For the OP, take a look at the RS232 DB9 pinout. You see that it is a trapezoid shape with pins 1-5 in one column and pins 6-9 in another. Basically map them onto an IDC10 (the plug that your motherboard takes). The numbering on IDC is different, with pin 2 where pin 6 is on the DB9.
 
I checked all the pins, and unless something is lost in translation, the header I have seems ok.

My serial port is still not working. 🙁
I'm reading this as IDC10 plug pinout from the driection as if Im looking into the holes on the IDC

2-1
4-3
6-5=
8-7
10-9
The = is the key.

I have
idc 1 to db9 1
idc 3 to db9 2
idc 5 to db9 3
etc
7=4
9=5
2=6
4=7
6=8
8=9

The DB9 end is all 9 male pins in a housing, to have a mouse plugged into it.
I'm assuming that DB9 pinout linked above is for a male pin setup, and I'm looking at the pin numbering based on that.

http://i42.tinypic.com/2zoxj40.gif

Unless I'm confused, this is the right header, but my serial port does not work. It's enabled in the bios. Windows says it's fine, but nothing, so it sure seems like this cable is the issue, but... Any ideas?

UPDATE: THIS page seems to imply a different wiring.
Maybe there is more than one setup for these header cables?

 

I can now confirm that there are definitely two different wiring pinouts for motherboard headers.
Asus does not currently use the pinouts described above - they use simple pin 1 to pin 1, pin 2 to pin 2 setup.

I resoldered my header cable and now my serial port is 100% working.
 
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