Motherboard USB headers?

[Whyzman]

I picked up an internal USB media card reader. Little did I realize the learning curve I was about to enter into...major S curve kinda stuff!

It has a 5 pin in-line connector. Most of the motherboard connectors, however, are setup to handle a dual USB scenario (i.e. a 9 pin connector that provides for two additional USB ports).

Looking over the wiring diagram it appears that I could indeed just use the 5 pin on one portion of the header. It appears that the other half of the header could still possibly use a 5 pin, but one of the pins (shell connector I think they call it) would not make contact with the header on the other portion...because there's no pin for it to engage in the number 9 or 10 spot.

So, I 'm wondering if this is a problem or if the shell connector (black wire) is essentially a redundant ground?

Also, I've used up the 2 internal USB connectors available on my motherboard. Is there some type of 5 pin splitter at the motherboard level that would allow me to plug it in?

Does an external USB hub essentially accomplish the same thing...or, is there circuitry that regulates each of the devices one would plug into it?

Questions questions...your help would be much appreciated! The rack and pinions attached to my poor brain are really taking a beating on the curves...

[Paul Komski]

This is a horribly non-standardised area. There are usually three basically different types of mobo headers (so far); ones with 8, 9 and 10 pin headers. The 10 pin ones are the ones to be most careful with since the top row and bottom row are virtually reversed from the top and bottom rows on those with 8 and 9 pin headers.

On 8 and 9 pin headers the wiring is essentially the same up to pin 8

2 4 6 8 (for port1)
1 3 5 7 (for port2)

1 and 2 for 5V (usu red)
3 and 4 for data- (usu white)
5 and 6 for data+ (usu green)
7 and 8 for ground (usu black)

On headers with 9 pins, position 9 has a missing pin and position 10 has the 9th actual pin. From looking at various front panel circuit boards that provide a 9th wire (also usually black) for position 10 on the mobo is often actually in contact with the casing/shielding and also to the two ground wires. So as far as I have been able to tell this is also a ground wire but one that goes to "overcurrent" sensing on the motherboard.

That at least is my understanding and I guess that your five wires would have the normal 5V, data-, data+ and then two ground wires which you would attach to positions 8 and 10 on 9-pin header or be twisted together onto pin 8 on an 8-pin header.

As for a splitter I just don't know how that would compare with the daisy-chaining that can take place with a sequence of USB ports - but I think you need a chain rather than a Y-splitter as such.

Any other feedback from peeps welcomed.

[Whyzman]

It is indeed confusing Paul! My ASUS board is from around January 2001 which is pretty close to the cusp of USB becoming quite mainstream. I only have the integrated USB ports and one header for additional.

Along with the motherboard ASUS sent a rear mount dual port USB that sits in a blank PCI slot. This of course has the "standard" 9 pin connector. I currently use 3 of the 4 possible connects for external devices. If I were to pull the rear dual port connector I could plug the card reader in, however, I then use functionality of both the rear ports.

I suppose I could get a PCI USB card...but I'm trying to slide by until I build a new computer. Most of the newer boards have up to 8 so I'd be covered...

This seemed like a pretty slick deal to start with as the reader slips into a 3.5 below my floppy drive so I don't have to find some place on my already overburdened desk.

Now just look what I've gotten myself into...

[Paul Komski]

Perhaps you could use something like
http://www.sfcable.com/Merchant2/mer...de=usbsplitter
or
http://www.networktechinc.com/hub-usb.html

I guess you'd have to cut off the reader's 5pin connector and then connect the wires directly to a Male/Female USB extension cable with the Female cut off and just leave the "overcurrent" wire alone (my guess is that it is probably connected to the normal ground wire inside the reader's circuitry).

[Whyzman]

Still doing some research Paul...found some interesting stuff:

http://www.frontx.com/cpx101_2.html

http://www.short-media.com/review.php?r=242

And this adapter...I could possibly connecto to the remaining external USB and route back inside...http://www.xpcgear.com/pinhead2usb.html

[Acmo5]

Search for "IDC 5 to USB A Male" or "Internal USB Expansion". one of these may fit your need