The nine pin layout is nice because standards are nice, but early USB implementation (especially with AT motherboards) was all over the place. I've a PCChips M520 that has a ten pin USB header and in that case the pins are the same as the nine pin. But there are also some motherboards out there like this illustration. If there is any doubt, you are best off to verify the +5 volt pins with a volt meter. The first time I connected a USB dongle to an AT motherboard back in 2001, I was saved by my power supply as it sensed the ground fault and wouldn't power up because I had a ground pin connected to a +5 volt pin.

I didn't easily find the manual for the K7T Pro, but I did find one for the Pro 2. It shows the USB header wired up as below. Perhaps your header is wired the same. It has two ground pins per port instead of the usual one ground pin, so that's why there are 10 pins instead of 8.

You may need to rearrange the pins on your breakout cable to match the motherboard.

Cosmic wrote on 2022-09-24, 16:44:

I didn't easily find the manual for the K7T Pro, but I did find one for the Pro 2. It shows the USB header wired up as below. Perhaps your header is wired the same. It has two ground pins per port instead of the usual one ground pin, so that's why there are 10 pins instead of 8.

You may need to rearrange the pins on your breakout cable to match the motherboard.

Or get one of these type:

I decided it's better to build an adapter, and not rewiring USB breakout cable.

Otherwise rewired USB cable may be later plugged into modern header by mistake and something may get fried or just not work.

Here it is, with criss-crossed wires on one side half of the adapter and straigt on the other.

I hate to break it to you, but if you twist that cable around so the ends are next to each other... the wires are connected straight through.

The pin diagrams in posts 2 and 3 of this thread are physically identical.

jmarsh wrote on 2025-11-02, 18:18:

I hate to break it to you, but if you twist that cable around so the ends are next to each other... the wires are connected straight through.

The pin diagrams in posts 2 and 3 of this thread are physically identical.

I'm not sure what you mean.
Diagrams in post 2 and 3 are two different 10-pins header designs. They are similar in that left and right side halfs are rotated 180 deg, so that the plug can be inserted any side.
My motherboard (by Acorp) uses one from post 2.

On the other hand, "standard" USB 2.0 output cables use 9-pin design, where the plug can't be rotated, and left and right side halfs are electrically identical.

UPD:
Now I understood what you say. No, I criss-crossed the wires on one half of my adapter, but not on the other. I hope you get the idea now 😀

Aha, well... the reason pin 9 is key and meant to be blocked in the plug is so that you can't accidentally plug it into the old style 10-pin connector.

I have a 10 pin header on my Acorp super socket 7 board and before I realised it I blew up the USB header with a modern bracket cable, something got shorted and smoked

NeoG_ wrote on 2025-11-03, 23:30:

I have a 10 pin header on my Acorp super socket 7 board and before I realised it I blew up the USB header with a modern bracket cable, something got shorted and smoked

How did you manage to do that, as normally modern ones have only 9 holes?

kolmio wrote on 2025-11-04, 07:46:

NeoG_ wrote on 2025-11-03, 23:30:

I have a 10 pin header on my Acorp super socket 7 board and before I realised it I blew up the USB header with a modern bracket cable, something got shorted and smoked

How did you manage to do that, as normally modern ones have only 9 holes?

There wasn't much light and it ended up offset by one row so the key was hanging off the edge

You could short either type of port if you misaligned the connector in the "right" way.