Internal COM port - 10 pin header

September 27, 2005 at 19:42:55
Specs: XP and W2K Server, 2.8 ghz 2 GB DDR


I have a new Tyan mobo with a 10 pin secondary COM port header. The pinout looks standard - I have the pinout diagram. (but I am no expert on hardware). I can't find a backplate with cable that is 10 pin here in Thailand and can't order one from the Internet. (It's a long story).

I am thinking of just opening up the closed 10 pin location on the female plug on the end of a standard backplate cable and plugging that in, but this is an expensive server mobo - I don't want to take a chance of harming it.

I wonder why some mobo would use a 10 pin when serial is all 9 pin now...

Anyway, what do you guys think - should I give it a go or do you have any other ideas?



See More: Internal COM port - 10 pin header

Report •

September 27, 2005 at 21:19:12

If you 'really' need another comm port, I would suggest a PCI card with comm ports.

Report •

September 27, 2005 at 21:30:15

I don't think the 10th pin is used. It's more of a key to make sure the cable is properly inserted. In some cases the plug will have the extra hole filled in (to fit a 9-pin socket) and in other cases it'll be open (to fit a 9 or 10 pin).

Now it's possible Tyan has modified the pin-out so the extra pin actually does something but I doubt it. You'd have to check with them on that.

I've also noticed the pin-out on those is often not standardized. One made for a particular board may not work with another. The only way I could tell was by connecting it up with a mouse and then booting with a bootdisk and see if a dos mouse driver would load.

Your best bet may be to try to get ahold of various 10-pin connectors and see which one works. I have several dozen of them around here but live in the US.

Report •

September 27, 2005 at 22:11:31

Dumpster diving. Else fabricate one. There were two semi standards for the serial cable. One using IDC connectors on both ends, usually DB9-P, and the other with the socket end soldered. Most newer cables have only the 9-pin connectors. You can get a cable and connector using a floppy disk or IDE cable and removing the unwanted conductors and pins. Many older computers use the cable to connect the serial ports either to the motherboard or to the io card. Look for an AT type machine since most don't have the connector on the motherboard.

Report •

Related Solutions

September 28, 2005 at 03:58:37

My main concern was the possibility of damage with the wrong pin assignment and as you guys haven't mentioned that and I found no references to that anywhere on the web I think I am okay there.

Tyan support responded quickly but just said to buy the right cable (even though the manual says use only the supplied one but one was _not_ supplied). Not much help as nobody I can find including the Tyan dealer has or will try to locate one here. If Tyan doesn't come up with anything else I think I will just again compare the pinout on the internal header (#10 is marked N/C) with a standard 9 pin thingy and if the same modify it to make it fit.

Thanks for the input, I appreciate it.


Report •

September 28, 2005 at 10:08:40

As long as the header/ connector plugs in, you won't ruin anything UNTIL you actually hook something to the serial port (DB-9)

Therefore, you should be able to connect a DB-9 adaptor cable, and then use some method of confirming pinout before you use it--in safety.

There is a wealth of info on pinouts on the internet, do you have one of the popular little troubleshooting modules, or a meter, or a breakout box?

Report •

Ask Question