Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I've currently got a situation in my PC where I have 3 devices that connect to the motherboard via the onboard USB pinouts.

The problem is, I only have two sets of USB pinouts on my motherboard.

Is there any way of connecting two devices to one set of pinouts? Essentially, I'm looking for the functionality of a USB hub, but I'd like it to be inside the case, and provide pinouts rather than regular USB ports.

Update: I don't need any more USB ports, I have devices that use the USB pinouts. I already have extra USB ports that aren't used, so adding an PCI USB card doesn't really help anything.

share|improve this question
Did you find the info you needed? Did that comment I added to my answer make sence to you? – Troggy Aug 17 '09 at 14:58
No, you need more USB ports or use a hub. Two USB devices cannot electrically share one port. There has to be a hub controller (which is a special type of USB device) in order to "share" one USB port. Open up a "passive" hub to see that is not wired like you think. – sawdust Sep 25 '15 at 1:46
up vote 5 down vote accepted

Another option is an internal USB expander -- this is basically a hub that connects to internal power and a single motherboard USB header, and provides multiple USB headers and possibly some internal ports.

  • NZXT IU01 internal USB expansion -- 3 headers, 2 internal ports (8 ports total). Available at various internet retailers.

    alt text

  • iBuyPower IES system -- 2 headers, 1 internal port (5 ports total). Have not seen it available except from iBuyPower; does not appear to be available for online ordering from the manufacturer.

    alt text

These appear to be very niche products; I'd like to know of other similar products.

share|improve this answer

If you mean like this:

enter image description here

Then yes it is technically possible, but there are drawbacks:

But if one or both devices draw power FROM the USB header then the wheels fall off. A device connected to the USB header will hang onto the connection even if the software for it is shut down and the device is "powered off."


share|improve this answer
If you understood USB and how a USB hub works, you would not even consider doing such such a kludge. – sawdust Sep 26 '15 at 6:08

You could go about this a couple ways. The easiest is to buy a cheap $10 usb card with another usb header on the card that you could connect to. This way you do not jerry rig anything and do not endanger us all. ;):

Or there is an adapter that goes male usb header to USB A: Not sure if this would actually work with the device you have though.

And here is the pinout's you requested:

share|improve this answer
+1 for good advice. :-) – hanleyp Aug 17 '09 at 2:47
Good info but I don't need any more USB ports, I have plenty, so the addon card doesn't help at all. I need more PINOUTS. The adapter you linked might work, but I'd prefer something totally internal if possible. – TM. Aug 17 '09 at 3:06
TM. The card linked above has two USB headers (which I think you are calling PINOUTS). – hanleyp Aug 17 '09 at 3:23
Yah, I know you don't need more USB ports, but that card comes with an extra on-board "USB pinout" as you are calling them. It makes it really easy and you don't have to do any extra soldering or splitting wires. You also will not run into the power problem hyperslug mentioned. It is cheap, reliable, safe, and very quick. Also, look at the pictures on that newegg card and you will see what I mean. – Troggy Aug 17 '09 at 4:08… – Troggy Aug 17 '09 at 4:10

Update from below: There is a hack to add an internal USB hub to a UMPC. Maybe this is what you are requesting.

alt text

Here is another USB Internal Hub which has a PCI bracket:


You would have to use a hub to connect two devices to one USB header. One 4 or 5-pin USB header = 1 USB port.

Two devices on one USB port cannot work reliably at the same time. The reason for this is (this is from memory, so it may be a little out off or missing steps):

  1. Once a device is plugged in, it performs a hardware handshake with the controller.
  2. The controller then tells the OS that a device was plugged in.
  3. The OS detects what the device is and loads the correct drivers.
  4. The driver polls the device periodically to see if there is anything to communicate and performs the transactions until the device is removed.

USB is a very host software driven interface compared to other I/O. If a second device is connected to the same wires, it could potentially cause the first device to disconnect, cause errors in the transactions, or take over the connection.

Another problem is each USB port is limited by specification to be able to supply 5V @ 0.5A max current. If two devices draw power off the port, it could trip the overcurrent sense or a resettable fuse causing the port to fault.

share|improve this answer
This is factual but doesn't address the question. I realize all of this and in fact in the question I mention that I need a hub specifically. I'm just wondering if an internal hub even exists for purchase or can be built relatively easily. – TM. Aug 17 '09 at 3:11
So you have 3 internal USB devices with plugs and go onto the headers, but only have 2 internal headers? It is pretty easy to solder a USB plug to a header. I'll look for hubs which have headers. Usually they only are provided on a mother board and hubs have type-A plugs. – hanleyp Aug 17 '09 at 3:17
Soldering is easy if you have a soldering iron and solder, that is. – hanleyp Aug 17 '09 at 3:18
Lots of USB cards have internal ports as well. For example this StarTech 4 EX + 1 IN Port USB 2.0 PCI Card Model PCI420USB: – hanleyp Aug 17 '09 at 3:21

Go to AliExpress and order a 9Pin USB header to Quad 9P Female Extension Cable Desktop Motherboard 9-pin 1 to 4 Port multiplier Card HUB Adapter.

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .