USB 2.0 flash "key drive" tip

Discussion in 'Buying Tips, Advice and Discussion (archive)' started by jxyama, Feb 4, 2004.

  1. jxyama macrumors 68040


    Apr 3, 2003
    just wanted to throw a piece of advice...

    USB 2.0 enabled flash "key drives" draw too much power to be used on USB ports on apple keyboards.

    this was a surprise to me and a little inconvenient because i now have to plug it directly into the USB port on the back of the PowerMac...

    so if you are looking to buy one and would like the convenience of being able to use it on the desktop (i.e. at the keyboard), don't get the USB 2.0 enabled version.

    (if you have a USB 2.0 enabled PM right on the desk, then by all means, get the 2.0 enabled ones, of course...)
  2. thehuncamunca macrumors 6502

    Jul 9, 2003
    are you sure?
    i used a san disk 128mb usb2.0 in a flat panal imac's keyboard usb port and it worked fine
  3. jxyama thread starter macrumors 68040


    Apr 3, 2003
    hmm... maybe it depends on the drive manufacturer. some may go over the power limit, others don't...

    maybe i just got unlucky. :(
  4. johnnyjibbs macrumors 68030


    Sep 18, 2003
    London, UK
    I thought the USB ports on the keyboard were still only 1.1 though? That would mean that even if they did work, they would operate at slower speeds compared to the ports in the back of the machine itself.
  5. Westside guy macrumors 603

    Westside guy

    Oct 15, 2003
    The soggy side of the Pacific NW
    It's the difference between "self powered" and "bus powered" USB hubs.

    Any USB device can require up to 500mA off the USB bus and still be compliant with the spec.

    With a bus powered hub (which a keyboard is, in essence, when it provides additional USB ports) this means all the objects in the USB chain can only pull a maximum of 500mA total, since they're all getting power from the single USB port on the computer. But if you have two devices, each of which wants 300mA, this setup won't work.

    Self powered hubs have their own power supply, and so have no problems providing up to 500mA to each device.
  6. SilentPanda Moderator emeritus


    Oct 8, 2002
    The Bamboo Forest
    You might also consider just getting a USB extension type cord and letting one end sit up on your desk or something of that nature. That's what I do for my heaphone jack.
  7. jxyama thread starter macrumors 68040


    Apr 3, 2003
    right, i know. i didn't get the USB2 keydrive because it was USB2. i got it because it was $10. :p

    anyway, yeah, i knew about the hubs and such... i just didn't think it through, i guess. it's not a big deal, but thought it might be a good point to be mentioned.
  8. keysersoze macrumors 68000


    Jan 6, 2004
    Hmm. This brings up an interesting point. I have a San Disk 128MB minidrive like someone else who wrote earlier.

    When I first bought it, it worked in an iMac 233 (Old!) keyboard USB port. At some point I erased the San Disk completely using my iBook G4's disc utility. Now when I plug the San Disk into the iMac 233 keyboard, I get an error message that says it can't access the San Disk because there is no power available. So somehow I created a scenario where it worked at first...but no more??

    So now the San Disk will only work plugged directly into the iMac's main USB port.

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