I recently bought a USB hub because I find myself needing more than just two USB ports on my prebuilt laptop. However I come to the problem that when I use an external hard disk with it I cannot navigate to the hard disk, (including from My Computer on Windows or using cd E: on cmd). I've tried my other flash drives as well, and they don't work with the Hub either.

A problem I encounter is that Windows complains about an "Unrecognizable device" and fails to "download the drivers". When attempting to use the external hard disk normally (directly plugged in to this computer, or my workstation) it seems to have been "damaged from my misuse". Also, it appears as "Hard Drive FAT-32" instead of its original name.

My USB hub has the following specifications:

USB2.0 Super Hub Specifications:

Interface: USB2.0, Compatible with USB1.1

Data Transfer rate: 1.5Mbps/12Mbps/ up to 480Mbps

Bus-Power Limit current protection: 500mA

(PS I was able to repair it with some utility applications, namely disc doctors. To think it was named Super Hub... ha!)

  • Devices that doesn't demand data transfer works fine with the hub. (Such as a wireless mouse)
  • Flash drives and my Hard disk seems to break with it.

This is a sole problem of the hub and when plugging in directly, my devices works fine.

Am I using a USB hub wrongly, or are such hubs known to be defective with demands of data transfer and or is there a way to fix them?

(I've seen other similar questions but the answers seems to be related to the power supply. I've triple checked my Hard disk specifications and it demands less power than the Hub can relay, supposedly.)

Additional (unimportant) information: The hub has seven ports and has a switch for each port, but I usually only use one to three ports at once, for mechanisms such as external cooling and charging my phone. Those works fine.

I've never had much experience with using Hubs before so I would really appreciate it if anyone can give some information on what I can do to diagnose it. Or, are there a specific type of USB hubs I should buy instead (for compatibility)?

  • 1
    The 500mA limit is for the entire hub. So if you have multiple devices they will get less than that. It's never a good idea to use an external hard drive with an unpowered USB 2.0 hub. Still, I would expect the flash drives to work OK, if a little slowly. Have you tried using a different cable to connect the hub to your laptop? What brand is the hub? If it's a really cheap one (e.g. $5) I would throw it in the bin as it's likely to be more trouble than it's worth. – James P Jun 24 '14 at 10:12
  • @James Oh, since I was testing out the new peripheral I only connected one device at a time. I'll try connecting a different cable now, and I agree on the "cheap device" part - made me laugh :p – Unihedron Jun 24 '14 at 10:16
  • @James Huh, connecting the drive onto the hub onto a cable before connecting it to my laptop works and now everything runs happily. (?!) Spectacular! I guess I could use the new set up. Thanks for the help! – Unihedron Jun 24 '14 at 10:31
  • I'm not sure I understand what you are doing differently. – James P Jun 24 '14 at 11:45

The problem description indicates that the damage is corruption due to data transmission errors rather than damage to the hardware.

This may be due to incorrect timing, incorrect driving voltages or incorrect terminating impedance. If increasing the length of the cable from hub to computer fixes anything, I would suspect an impedance mismatch, in which case small changes in cable length could have a large effect.

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