USB 3.0 card, USB 3.0 hub, USB 3.0 bandwidth not used by USB 2.0 devices


#1

My goal is to connect four USB 2.0 webcams – Microsoft LifeCam Cinema, which uses about 48% of USB 2.0 bandwidth – to my computer using USB 3.0. I added a Plugable USB 3.0 card to my computer, and tried two different USB 3.0 hubs (TRENDnet TU3-H4 and a D-Link DUB-1340). For both hubs, I can get just one camera to stream in parallel in the recording software I use, which likely indicates a bandwidth issue. Before attempting USB 3.0, I managed to get 2 cameras to stream per internal (motherboard) USB 2.0 host controller, but lost streaming for one of the cameras, e.g., once mouse and keyboard were on the same host controller. And the issue is not a power issue; the cameras require 0.5 A each, while the hubs have 4 A power supplies.

I checked the Device Manager on Windows 7, and the D-Link USB 3.0 hub appears as both “Renesas Electronics USB 2.0 Hub” and Renesas Electronics USB 3.0 Hub." The “Parent” property of the LifeCam appears to point to the 2.0 Hub and not the 3.0 Hub, which, in turn, may be the reason I run into what looks like bandwidth issues. I tried disabling the “Renesas Electronics USB 2.0 Hub,” but then the LifeCams are no longer recognized.

Any suggestion? Thanks,

Uli


#2

Hi Ulrich,

Thanks for your question, and all the great detail. The problem you are running into stems from the fact that your USB 3.0 hub will operate as a USB 2.0 hub when USB 2.0 devices are connected. So the same bandwidth constraints apply.

However, you should be able to connect two cameras to your PCI-e USB 3.0 ports and two cameras to on board USB 2.0 ports on your computer.

Give this setup a try and let us know how it goes. We’ll be happy to help.

Thanks,
Jerome

Plugable Technologies.


#3

Hi Jerome,

Thanks for the quick reply. I had already tried your suggestion and it works. I had hoped to use the USB 3.0 card to scale up to, say, 8 cameras.

Two more questions:
* is the issue due to the USB 3.0 spec and every USB 3.0 hub and card will have this issue? I had checked with TRENDnet support, and they claim their TU3-H4 hub can support 4 “concurrent” USB 2.0 devices each at full USB 2.0 bandwidth.
* I assume I cannot “trick” the USB 3.0 hub into making all connected devices appear as USB 3.0 on my computer by plugging a USB 3.0 device into one of the ports? (Do not have a USB 3.0 device currently to test this.)

Thanks,

Uli


#4

Hi Uli,

I’m glad to hear that your current setup is working. To get up to 8 cameras, you could add a PCI card (or two) with additional USB ports. I can’t speak to the capabilities of the TRENDnet card, but that functionality would be an extension of the USB 3.0 spec.

When you do find a solution we’d love to hear how you worked it out.
Thanks,
Jerome.

Plugable Technologies


#5

Hi Ulrich Stern, have you found a solution? I have the same problem as you too. I’m using another brand of UBS 3.0 hub.

Joan


#6

Joan,

I have not found a solution to use USB 3.0 bandwidth with USB 2.0 devices.

And things can even be worse with USB 3.0 than with USB 2.0. E.g., using a NEC D720200 (USB 3.0)-based card I got only one LifeCam to work, while I got two of them to work on a NEC D720101 (USB 2.0)-based card.

I tried several USB cards. I like cards with the D720101 since each chip gives me two additional cameras. I would have loved to get the discontinued IOI Technology Corporation U2-PCIE10 which has two D720101, but they replaced it with a card that has a MosChip MCS9990, which sounds great in theory (4 independent USB 2.0 host controllers), but that chip worked so unreliably with my LifeCams (they would turn off randomly, usually after just a minute or so) that I could not use it.

Cheers,

U*


#7