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USB wiring mystery

By kenrogers ·
Everyone loves a mystery! Here's one re USB wiring. I have a computer with a motherboard producing USB v2 at the rear two ports. Wiring hooked to the posts on the motherboard yield USB v1 performance. To get more USB v2 ports I've bought a PCI/USB card that has 6 v2 ports. Two of these are at the back of the card so inside the computer. I wired a plug to go from these two in the back of the card to the slots in front using the same wiring that formerly plugged onto the motherboard. It's a standard USB plug and simple wiring: red/white/green/black + grounded shield, right?

It doesn't work at all!


What is so critical about USB wiring that slots wired like this to working slots won't work? I've soldered carefully, shielded, etc.

Thanks for any help/insight.

Ken Rogers

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Pairing, And:

by TheChas In reply to USB wiring mystery

Are you following the correct pairing when you wire the cables?

Red and Black should be power and ground.

Green is Data + and White is Data -.

Then, you need to make sure that you are wired to the correct pins on the front port connector.

1 - +5
2 - Data -
3 - Data +
4 - Ground

On a 10 pin header, typically there is only one shield connection.

The quality of your connections and how far back from the board you have the wires un-twisted can have a major impact on USB data signals.

It is possible that the board or connectors for your front panel jacks only support USB 1.1

As to your on-board ports running at USB 1.1 speed. Check the manual to make sure they are USB 2 ports. If so, the problem was / is the wiring.


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probably wiring to front

by kenrogers In reply to Pairing, And:

Yes, I carefully followed the power, signals and ground conns and checked for continuities/shorts with an ohmmeter. The motherboard is USB 2 and this works on the installed ports coming off the back. Wiring to the front yielded v1 performance from day one. I have no manual for the housing, which has the cables going to the front slots. Maybe they are v1. I did the wiring from connector to the port at the back of the new PCI/USB 2 card to the front ports using shortest runs and twisting the data lines together, shielded with aluminum foil, etc. So it must be the basic wiring/slots are v1 and as you conclude, I guess "the problem was/is the wiring."

Anyway I now have lots of v2 jacks at the back! :)

Thanks for the reply.


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