USB hub to USB hub interconnection

Discussion in 'Computing and Networks' started by Ryan_Shephard, Jul 18, 2011.

  1. Ryan_Shephard

    Thread Starter Member

    May 9, 2009
    18
    0
    I may be stompping over old material here.... (Please link relevant info if necessary, as did not find...)
    Was wondering if it is possible (sufficient ampacity, signal issues, etc.) to run a 4 port USB hub upstream from a 7 port USB hub? (If the 4 port need be externally powered to make this work, please let me know).

    thanks
     
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    If I get the question right you want to plug in the 4 port hub into a 7 port hub?
    From Wikipedia: "The USB specification requires that bus-powered hubs may not be connected in series to other bus-powered hubs."

    So question is, is your 7 port hub self-powered or bus-powered. If it's bus-powered depending on what you connect you will soon run into problems, as the bus won't be able to supply more than 500mA (in general).

    With bus-powered hubs I often had already problems connecting only three devices to it.

    http://en.wikipedia.org/wiki/USB_hub
     
  3. Ryan_Shephard

    Thread Starter Member

    May 9, 2009
    18
    0
    Both the 7 port, and 4 port hubs would be externally powered.
    The 7 port at 3.5A, and the 4 port at 2A (Industrial DIN rail units).

    So the downstream power drain issue would not be a problem.
    My main concern in correct, consistant communication. (AKA, will the downstream hub maintain it's devices' IDs through the 7 port, or will this become a nightmare?)

    Expanding on this note, could there be several externally powered 4 port hubs downstream of said 7 port? And would they remain reliable?
    Routing this way would allow use of the server's limited USB ports (2), and reduce downstream wiring clutter and conduit size requirements.
     
  4. Ryan_Shephard

    Thread Starter Member

    May 9, 2009
    18
    0
    Nevermind...Sorry for space wasting... Found out what I needed to know.
     
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