USB hubs?

Discussion in 'Computer Support' started by Dave, Jan 11, 2008.

  1. Dave

    Dave Guest

    Are there any restrictions that come with using USB hubs. It's just
    that some devices obtain their power via the USB connection. I'm
    thinking that if you have a number of such devices connected they all
    can't take their power from the same connection. Is this the case? And
    are there any data transfer restrictions involved as well?

    Many thanks for any advice,
     
    Dave, Jan 11, 2008
    #1
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  2. Dave

    richard Guest

    On Fri, 11 Jan 2008 09:03:03 -0800 (PST), Dave <>
    wrote:

    >Are there any restrictions that come with using USB hubs. It's just
    >that some devices obtain their power via the USB connection. I'm
    >thinking that if you have a number of such devices connected they all
    >can't take their power from the same connection. Is this the case? And
    >are there any data transfer restrictions involved as well?
    >
    >Many thanks for any advice,


    Not really. It's a matter of what requires power and what does not.
    Most of my stuff is self powered.
    What limits the power usage is your power source from the computer
    itself. Like any other electrical devices, plug in too many and zap!
    Right now I've got like 5 or 6 devices connected with no problems.
     
    richard, Jan 11, 2008
    #2
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  3. Dave

    Mike Easter Guest

    Dave wrote:
    > Are there any restrictions that come with using USB hubs.


    Of course.

    > It's just
    > that some devices obtain their power via the USB connection. I'm
    > thinking that if you have a number of such devices connected they all
    > can't take their power from the same connection. Is this the case? And
    > are there any data transfer restrictions involved as well?


    wiki sez:
    " Initially, a device is only allowed to draw 100 mA. It may request
    more current from the upstream device in units of 2 mA up to a maximum
    of 500 mA.

    " If a bus-powered hub is used, the devices downstream may only use a
    total of four units - 400 mA (i.e. 2 watts) - of current. This limits
    compliant bus-powered hubs to 4 ports. The host operating system
    typically keeps track of the power requirements of the USB network and
    may warn the computer's operator when a given segment requires more
    power than is available.

    "On-The-Go and Battery Charging Specification both add new powering
    modes to the USB specification. The latter specification allows USB
    devices to draw up to 1.5 A from hubs and hosts that follow the Battery
    Charging Specification."
    http://en.wikipedia.org/wiki/Usb


    Also realize there are usb 1, 2, and 3 on the board.


    --
    Mike Easter
     
    Mike Easter, Jan 11, 2008
    #3
  4. Dave

    olfart Guest

    "Dave" <> wrote in message
    news:...
    > Are there any restrictions that come with using USB hubs. It's just
    > that some devices obtain their power via the USB connection. I'm
    > thinking that if you have a number of such devices connected they all
    > can't take their power from the same connection. Is this the case? And
    > are there any data transfer restrictions involved as well?
    >
    > Many thanks for any advice,


    the power from the computer USB to the Hub is limited. Get a powered Hub
    which has it's own power supply and you will be OK
     
    olfart, Jan 11, 2008
    #4
  5. Dave

    sdlomi2 Guest

    "olfart" <> wrote in message
    news:...
    >
    > "Dave" <> wrote in message
    > news:...
    >> Are there any restrictions that come with using USB hubs. It's just
    >> that some devices obtain their power via the USB connection. I'm
    >> thinking that if you have a number of such devices connected they all
    >> can't take their power from the same connection. Is this the case? And
    >> are there any data transfer restrictions involved as well?
    >>
    >> Many thanks for any advice,

    >
    > the power from the computer USB to the Hub is limited. Get a powered Hub
    > which has it's own power supply and you will be OK
    >

    For devices requiring marginally more power, I think??? I've seen usb
    splitter-cables--a y-cable with 2 ends that plug into 2 computer usb
    ports(in this case, 1 hub port and 1 computer port) and then its 3rd end
    plugs into the device. s
     
    sdlomi2, Jan 14, 2008
    #5
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