The cables from the mainboard to the connector are not standardized. You need matching parts. There was a topic on this already.

Damn, I never suspected a pin-out issue... but I'm glad I asked, just when I was about to strip the board of its goods (cache, jumpers, BIOS chip, battery holder) and throw it away. After some searching (found out there are two possible pin-outs for these cables), I took all the serial ribbons I could find, opened their DB9 connectors, selected one that didn't look like a non-working one, used a needle to draw a hole for the 10th pin (probably the reason I didn't use it in the first place), and successfully tested it with the serial mouse.

So, this short thread not only taught me something, but saved a perfectly good 486 PCI board from extinction - many thanks are therefore in order 😀.

Julianv, could you let me know exactly what pin on the 4DPS COM A port is supposed to go to which pin on the male end of the DB9 cable? The pins on the 4DPS are labeled 1-10, and labeled 1-9 on the DB9 cable. I am using mouse.com with test.exe to test the serial mouse, but have not had any luck in getting the serial mouse working.

The serial controller chip on this board is a Winbond W83768F. It is the same serial controller chip on a DTK PKM-0033S. I can easily get the serial mouse working on the DTK board. I checked the pin-outs on the DTK board's COM header vs. that of the DPS COM header - on both boards, the pins go to the same location on the serial controller chip (Winbond W83768F). From this, I know that the cable needed is 1-to-1, that is pin 1 on the header goes to pin 1 on the male DB9, pin 2 to pin 2, etc.

But for whatever reason, on 2 different 4DPS boards, I cannot get a serial mouse working with mouse.com/test.exe

Any ideas would be most appreciated.

EDIT:
This is what another forum goer found the pin assignments to be on version 1 of the board,

133MHz wrote:

[…]
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1IDC   DE9
2 1     1
3 2     6
4 3     2
5 4     7
6 5     3
7 6     8
8 7     4
9 8     9
10 9     5
11 10    x

From this post:
My first 5x86 build (also motherboard component level repair)

Julianv, what revision of the board are you using? Are these the pins you determined worked? I should reconfirm my "486 serial cable" is using these pins. I wonder if different board revisions used different pin assignments. I have two rev 2.1 boards.

I do not have any cable configurations like that posted in that other thread. Are there in fact 3 serial cable designations? The two cables I have are as follows,

IDC DB9
1 - 1
2 - 2
3 - 3
4 - 4
5 - 5
6 - 6
7 - 7
8 - 8
9 - 9

IDC DB9
1 - 1
2 - 3
3 - 5
4 - 7
5 - 9
6 - 2
7 - 4
8 - 6
9 - 8

Even if the IDC connector is placed on backwards, I do not get that other guy's pin configuration.

The IDC pins numbers are as shown next to the COM header on the 4DPS motherboard. The DB9 pin numbers are as printed on the male DB9 cable.

For those who have a working serial port on the 4DPS board, could you let me know your pin configurations, BIOS revision, and BIOS settings you are using? Thanks!

EDIT:

Interesting, this website lists the IDC pin numbers as follows,
http://pinouts.ru/SerialPorts/Serial9_pinout.shtml

1 2
3 4
5 6
7 8
9 10

whereas the 4DPS board lists the IDC pin numbers as,

1 6
2 7
3 8
4 9
5 10

I have confirmed that the 4DPS v2.1 uses this style cable,

IDC DB9
1 - 1
2 - 2
3 - 3
4 - 4
5 - 5
6 - 6
7 - 7
8 - 8
9 - 9,

whereby the IDC # corresponds to what is printed on the 4DPS' PCB. It so happens my serial controller on my 4DPS is dead. On another 4DPS, the floppy controller is dead. I received the boards like this. I figure since the 4DPS has a working PS/2 port, a serial port is of lesser importance than the floppy port. It may be that a lot of these boards from the Ukraine have been handled incorrectly at some point and get damaged due to static discharge.

The serial port usually consists of the "UART" ASIC and a level converter chip. If the latter is broken there is a chance to replace it as they are usually smaller chips.

Well, nope, on this mainboard it's an uncommon chip: W83768, it takes some skill and equipment to replace this kind of package if you actually find one to buy.
It also contains parts of the gameport.

One last thing to check is that your +12 and -12V lines to the mainboard are okay.

It might be best to just disable the COM ports and use a multi-io card.

Yes, the multi-I/O card works fine, however the board looses its native value.

The hooked-up PSU voltages are:

+12V = 12.30V
-12V = -11.75V
+5V = 5.12V
-5V = -4.94V

The SMD package for the W83768F looks to have about 1 mm pin spacing. Has anyone had any luck using solder wick to remove these without cutting the leads off? If so, what about using a very sharp Weller tip, such as the ETU or ETS to contact solder such a chip back on? I have another board I can try this transplantation with, however I give it a low chance of success.

I always thought com ports/pins configurations were standardized and universal across motherboards.

Until about a week ago when I got my hands on an EPOX EP-58MVP3C-M
Its a really nice board but I am missing the PS2, USB and COM Port headers/cables.

I tried all of the cables I had available for the com ports and nothing worked.

I noticed the same thing. When I plug the com port backwards into the motherboard ctmouse.exe would find a mouse but it obviously would not work.

the EP-58MVP3C-M uses a pin configuration like this:

1 6
2 7
3 8
4 9
5 10

Where do I find a cable like that?

rgart wrote:

I always thought com ports/pins configurations were standardized and universal across motherboards. […]
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I always thought com ports/pins configurations were standardized and universal across motherboards.

Until about a week ago when I got my hands on an EPOX EP-58MVP3C-M
Its a really nice board but I am missing the PS2, USB and COM Port headers/cables.

I tried all of the cables I had available for the com ports and nothing worked.

I noticed the same thing. When I plug the com port backwards into the motherboard ctmouse.exe would find a mouse but it obviously would not work.

the EP-58MVP3C-M uses a pin configuration like this:

1 6
2 7
3 8
4 9
5 10

Where do I find a cable like that?

Hi,

I'm not sure if you're still active in this forum... however.

I found this same board today and it was missing a COM port/cable, for my mouse.
However, I bought the COM port from ebay and refer to the manual below:-

Links:-
http://www.motherboard.cz/mb/epox/EP-58MVP3C-M.htm
http://www.elhvb.com/mobokive/Archive/Epox/ma … als/58mvp3c.pdf

Somehow, after cutting and rewiring.. and looking at the motherboard .pdf manual...etc... I got my mouse working.
1 Keyboard, 1 Serial Mouse, and i'm good to go. (I didn't bother about other ports, like printer...etc)

Hope this help!

For completion of information about this board, there’s a bug in the BIOS, which disables the floppy controller by default, while it’s set to enabled in the BIOS.

How to resolve that issue:
1. Disable floppy controller in the BIOS, save settings and reboot.
2. Enable floppy controller again, save settings and reboot.

It should work now.

The COM port issue is not being resolved by the same workaround, as I’m currently working on that same issue. I’ll have to dig more into the datasheet for that IC to get it to work I guess. The inputs and outputs on the datasheet are just numbered arbitrarily, so I’m thinking there has to be another way to connect or test this.

As you’ve mentioned, COMTEST.COM also shows a modem when connected with a wrong pinout (as do other IO-controllers), so that’s a good thing.

Next thing to try is to measure the traces on the motherboard. Maybe the rows on the IDC connector are swapped around on the motherboard layout? I’ll have to check.

Keeping you posted for more details.

I have this board (4DPS) as well, and the serial controller seems to *work*, but the cable I have doesn't (1-1, 2-2, etc).

The cable is the regular
2 4 6 8 10
1 3 5 7 9,

but the board is labeled

6 7 8 9 10
1 2 3 4 5

Is the board's pinout matching what the connections to the serial port would be? (1-1, 2-2, etc) I don't quite understand the conclusions reached here...

In this case, would I need to go ahead and make my own riser?
Or would the zig-zag type work here (and, how do I even search for it)

Any help would be appreciated! As well, apologies for necroposting, but I felt better that than create a whole new topic for the exact same issue

feipoa wrote on 2013-06-26, 04:23:

IDC DB9 1 - 1 2 - 3 3 - 5 4 - 7 5 - 9 6 - 2 7 - 4 8 - 6 9 - 8 […]
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IDC DB9
1 - 1
2 - 3
3 - 5
4 - 7
5 - 9
6 - 2
7 - 4
8 - 6
9 - 8

Looking at this, it's as if it uses this cable standard, but is labeled by the serial port pins and not the header pins on the board?

Correct me if I'm wrong though, and I still don't know what I'd search to even find a cable of this standard, other than making my own 😜

There are 2 'standards' - 'alternated' (for older boards/controllers ~486 and bellow) and 'in line' ( Pentium era and newer).