Omarkoman wrote on 2020-05-18, 03:42:

hi everyone […]
Show full quote

hi everyone

my pentium motherboard COM ports are not working, no matter what I try the mouse cursor wont move. eg tried different header cables, serial MS mouse, PS2 mouse with Serial to PS2 convereter, different mouse drivers. In bios set to auto or select specific COM port etc ... nothing works.

so I bought this PCI COM port card as it had a chipset that has DOS drivers available :

I found the DOS drivers and when I run the file, I get this :

note, on board COM ports are disabled in BIOS in this instance.

these are the command options but I have no clue how to set them up to get a comp port mapped and working :

any help would be appreciated ! thank you

There were several pinout standards for motherboard com port headers . The manual should specify what your board uses . Then you could rewire the header cable accordingly.

My best guess for the PCI thing would be to add a port and then remap it .

The manual

thanks, I found the manual too just now and when I do the nmdosin -a command, it doesnt add any ports 🙁

I will see if I can find the manual (or if someone can help that would be great) ... this is the board :

board also seems to have PS2 and USB headers? am I seeing that right? maybe I can get a connector with a bracket for one of those ?

Soyo 5VA2 , probably.

Found a manual, but no pinouts .

Found it .

Soyo uses type A pinout .

https://web.archive.org/web/19980210121317/ht … AQ/COMtable.htm

thanks but what that does that mean ? What do I have to do ? The case the mobo is in has a com 1 cable and I have few spare ones, how do I find a cable that has the right pint out connections?

Omarkoman wrote on 2020-05-18, 04:30:

thanks but what that does that mean ? What do I have to do ? The case the mobo is in has a com 1 cable and I have few spare ones, how do I find a cable that has the right pint out connections?

You can test the header cables you have using a multimeter to see if the pinout matches what is required . If one of your headers matches the pinout, great, use that one.

If none of them do, you could modify one of the ones you have to match the required pinout .

You will need a multimeter to check the pinout. To swap the cables around, you could cut and splice or solder the individual strands to match the required pinout .

ok, I can do that I think.

I assume though if none of the cables I have work, I will need to swap the right pinouts on one of the existing cables? Its just so strange, I never seen this before.

and in saying that, I wish I could get the PCI card going 🙁

COM ports are wired either (older standard)
12345
6789
or (newer standard)
13579
2468_
you usually can see the numbers on the corners of the header to see what is used.

The top row is what pins are used in the DB9 or DB25 connector in the backside of the case.

LPT port headers are always, that is only one standard.
13579...25
2468..24_

I have been cursing those COM cables more times than I can remember.

Omarkoman wrote on 2020-05-18, 05:03:

ok, I can do that I think.

Testing is not really necessary. When you pull the plugs out of the plastic casings the 2 different wiring methods are easily distinguishable.

yep, left is older standard, right the newer on. Thanks for that picture.

evasive wrote on 2020-05-18, 14:56:

yep, left is older standard, right the newer on. Thanks for that picture.

Old versus new or 'what is what' always confuses me for some reason....

If you are as old as me the newer, new newer, newest newer can be even more confusing at times 😀 Then again it all can be brought back to the basic components/functionality, a PC hasn't changed much in the last 35 years or so...

ok thanks guys, I checked the wiring and I can see all cables I have are the newer version.

Is there a simple visual guide I can follow to cut and reconnect wires to make it the older version pls?

thank you again for all the help, much appreciated ...

I've owned PCs since the early 90s and literally never have come across one of the "old" standard dongles

I ordered another PCI serial port card, comes with original drivers for DOS so hopefully it will work.

the rewiring, I dont now how to connect which wire where ... 🙁

I found a cable thats already the old version !!!!! so lucky !!! was burried in old box and it all now works !!!!

it also has a PS2 connector but its 1x5 so not sure which header to connect to on mobo and in which orientation

Omarkoman wrote on 2020-05-20, 03:04:

I found a cable thats already the old version !!!!! so lucky !!! was burried in old box and it all now works !!!!

it also has a PS2 connector but its 1x5 so not sure which header to connect to on mobo and in which orientation

There was info on the Soyo web site about the PS/2 pinout, but archive.org did not archive that one, unfortunately . The gif was named sy-ps_2.gif , if someone happens to have a dump of the Soyo website .