8

I understand that when I use a USB 2.0 devices on USB 3.0 ports, that I'm really just using a USB 2.0 bus along side the USB 3.0 bus. What I really need is a true USB 3.0 device that can act as a USB 2.0 host for other devices. That is, a USB 3.0 hub that hosts its own USB 2 devices without passing them to the root hub, or an adapter of sorts for the USB 2 devices to be compatible with USB 3 hosts.

My reason for this need is that I'm out of USB 2.0 bandwidth. I have a pro audio mixer using 65%, and an HD webcam that would like another 45% when it can get it. I found on my laptop that there is a single port exposed on another controller, where I attach my web cam. Even still, this doesn't leave much bandwidth available for other devices.

I would add another USB 3 host via Expresscard, but my laptop has no such slot.

I have plenty of USB 3 bandwidth available. It's hardly used by much of what I own. Is there an adapter that will let my USB 2 devices participate in the USB 3 network?

Improve this question
7
  • I'm not sure your assumptions in the first paragraph are correct, so I'm not really following what you're trying to accomplish. Is there any reference you can point us to that explains what underlies your question (or can you provide more detail as to what you think the problem action is)? That aside, USB 3.0 hubs are dirt cheap and work the way you describe by default. What's the problem with using one (any one, not some special one)?
    – fixer1234
    Feb 6, 2016 at 6:06
  • I have a related question if someone is interested in answering: Maximizing speed of USB 2.0 clients on USB 3.0 hub
    – Kozuch
    May 15, 2016 at 16:56
  • Is there more than one USB 2.0 controller in your laptop?
    – TheKB
    May 21, 2016 at 15:30
  • @TheKB There are two. One of which is for all the ports on the docking station and laptop, except one on the laptop. The other has all the internal stuff (camera, bluetooth, etc.) and a single port on the side of the laptop. I dock and un-dock frequently, so it would be very nice to not have to also plug something into that side port. Additionally, that one side port only does USB 2.0 and I have reached the maximum number of USB nodes so I cannot plug another hub into it. I have a USB 3.0 hub that has most small things attached, and anything needing more bandwidth is attached to the dock.
    – Brad
    May 21, 2016 at 17:35
  • What is the model of your laptop?
    – speeder
    May 22, 2016 at 14:54

3 Answers 3

Reset to default
7
+250

TLDR: Try using USB over IP instead of USB2 over USB3.

A quick googling shows that your exact question is not possible. https://en.wikipedia.org/wiki/USB_hub#Transaction_translator

Any USB 2.0 hub that supports a higher standard than USB 1.1 (12 Mbit/s) will translate between the lower standard and the higher standard using what is called a transaction translator (TT). For example, if a USB 1.1 device is connected to a port on a USB 2.0 hub, then the TT would automatically recognize and translate the USB 1.1 signals to USB 2.0 on the uplink. However, the default design is that all lower-standard devices share the same transaction translator and thus create a bottleneck, a configuration known as the single transaction translator. Consequently, multi transaction translators (Multi-TT) were created, which provide more transaction translators such that bottlenecks are avoided.[5] Note that USB 3.0 hubs do not currently perform transaction translation to super-speed for USB 2.0 devices.

However. On a related note, what IS possible, is to encapulate the USB 2.0 across TCP/IP over Fast/Gigabit Ethernet.. Essentially building a Transaction Translation module.

You could then connect the USB 2.0 devices to a lightweight PC that tunnels the USB over a ethernet connection. I would advice you use Gigabit ethernet, given that you have bandwidth requirements (please don't try to use Wifi). You can therefore run a gigabit ethernet over USB 3.0 on your laptop.

However, on your IP/USB hub side, your options are more limited.

You'd want a "low" cost single board PC with both a gigabit ethernet and a USB 2.0 (or better) controller.

I would suggest you take a look at the Banana Pi, which has a single USB 2.0 controller (2 ports) and a gigabit ethernet controller.

Even so. I'd expect pretty high latency on the link, which would make your Pro Audio Mixer useless. Luckily the HD Cam should work with the high latency (given it already is pretty high latency already).

All in all, I'd expect this project to run into ~100USD.

Edit:

My recommendation now would be to use the Orange Pi Zero Plus. It is a small SBC with GbE and a USB2.0 connector, and not much else.

Improve this answer
3

Because of the discussion here, I need to remark that the poster is correct and a USB 2.0 bandwidth limit does exist, as distinct from USB 3.0 bandwidth.

Wikipedia USB has this to say :

Because there are two separate controllers in each USB 3.0 host, USB 3.0 devices transmit and receive at USB 3.0 data rates regardless of USB 2.0 or earlier devices connected to that host. Operating data rates for earlier devices are set in the legacy manner.

USB over IP

Using USB over IP adds some possibilities :

FlexiHub (free software) if you have available another spare computer :

FlexiHub is a free USB over IP software solution, i.e. it enables sharing access to USB and COM devices over Internet or LAN. The solution is cross-platform – it works with Windows, Linux or Mac.

VirtualHere is another free software product.

USB Redirector - free between Windows-based computers.

Hardware : Some products exists, such as SIIG USB over IP 1-Port ($59.99) (but more can be found by searching Amazon) :

image

Improve this answer
8
  • Thanks for the reply. Option #2 is what I'm looking for, or looking to prove doesn't exist. The device you linked to is purely a plug adapter and will not work. I have also tried other USB 3.0 hubs, but again they just serve as a USB 2.0 hub for the USB 2.0 bus, and do not translate from USB 3.0 to 2.0.
    – Brad
    May 21, 2016 at 17:38
  • That's what I was afraid of - that nothing can disguise USB2 as USB3. Manufacturers have no reason to make such an adapter - your problem of USB2 bandwidth is not very frequent. What is your computer model? - There might other connectors one can connect to an additional USB port. Are you knowledgeable in hardware hacking?
    – harrymc
    May 21, 2016 at 19:15
  • All external ports except one are on the same bus. This includes the docking station. There is one external port which shares the same bus as all the internal USB components (bluetooth, touchpad, etc.). Currently I have to plug things into this port, but I dock and un-dock frequently... I was hoping to find a solution where I could use my docking station for fully docking. It's a Lenovo T440p. I have the same problem on a T450s.
    – Brad
    May 21, 2016 at 20:18
  • I don't fully understand the problem, since the bus is distinct from the controller. According to the doc, the Lenovo T440p has 3x USB 3.0 ports and the dock has further 3x USB 2.0 and 3x USB 3.0. So why do you have to put everything on one USB 3.0 port?
    – harrymc
    May 22, 2016 at 14:15
  • 1
    @harrymc The number of ports doesn't have much to do with the internal USB controllers. His laptop probably has a single Intel USB controller, that USB controller probably uses a design where it has internally 2 separate integrated circuits, one for USB 2.0 and one for 3.0, when you plug a USB 2.0 device, on any port on the machine, it uses the 2.0 circuit, even if it was plugged on a USB 3.0 port. what Brad is asking is how to force the use of the 3.0 circuit with a 2.0 device.
    – speeder
    May 22, 2016 at 15:01
2

Your understanding isn't correct. The USB 2.0 controller you think is "somewhere upstream" is inside your USB 3.0 controller chip. So a USB 2.0 device plugged into it is not using USB 2.0 bandwidth from some other 2.0 controller in the system. (It would not actually be possible for this to happen; the connection topology wouldn't permit it.) So you don't need a "USB 3.0 client". Just plug your USB 2.0 device into your USB 3.0 port.

Improve this answer
6
  • I should clarify that I'm talking about the use of hubs here. If I have a USB 3.0 hub, that's really just a USB 3.0 and USB 2.0 hub in the same package, with separate data lines in the same cable going to the host, correct? If it wasn't, then why would Windows say that my USB 2.0 audio device is using 65% of available bandwidth? That shouldn't be possible if it the hub was truly interfacing between USB 2.0 and USB 3.0.
    – Brad
    Feb 7, 2016 at 17:27
  • 1
    @Brad: USB 3.0 adds additional wires to what is in USB 2.0. The additional wires are used for the higher speed data transfer via a different protocol. If you plug in a USB 2.0 device, it lacks the extra wires, so the extras on the other side of the connector are just dead metal. If only the USB 2.0 wires are used, it operates as USB 2.0. That will even happen if you plug in a USB 3.0 device too slowly; if there is too much delay after the USB 2.0 wires connect before the extra USB 3.0 wires connect (they're located behind), it will be treated as a USB 2.0 device.
    – fixer1234
    Feb 9, 2016 at 5:13
  • @Brad There is no conversion from USB 2.0 to 3.0 in a 3.0 hub. As fixer1234 said there are separate wires in the 3.0 connector and cables for the 3.0 connections. The 2.0 devices use the same connector pins and wires they always have, all the way back to the controller in the PC. But the controller in the PC provides both 3.0 and 2.0 (and 1.1) functionality. The 2.0 bandwidth it provides is in addition to the 2.0 bandwidth provided by any other USB 2.0 controller in your machine. So your USB 2.0 device in the USB 3.0 hub has a whole new USB 2.0 bus's worth of bandwidth.
    – Jamie Hanrahan
    Feb 9, 2016 at 5:50
  • This information seems to conflict. I am aware of the other data pins and separate protocol in play, which is why I post my question. Everything in the comments here would indicate that USB 2.0 and USB 3.0 are separate but might be attached to the same root host controller. For the purposes of a USB hub, I don't see how a hub's worth of data on USB 2.0 will encapsulate or otherwise move to the USB 3.0 lines if the hub doesn't do that.
    – Brad
    Feb 10, 2016 at 6:17
  • Ah, there's the rub. The USB 2.0 traffic doesn't "encapsulate or move to the USB 3.0 lines". No one is claiming that it does. The hub doesn't do that, and the controller doesn't do that either. The host controller implements both USB 3.0 and 2.0 (and 1.1) functionality and interfaces both to PCIe or whatever your backplane bus is.
    – Jamie Hanrahan
    Feb 10, 2016 at 6:39

You must log in to answer this question.

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