Scanner/Web Cam numbering USB hub conundrum

[RAH]

Hi,
2 possibly related questions here:
1. I am running Windows XP home and have had reason (due to other issues) to
disconnect and reconnect various USB devices from my PC.

When I look in Control Panel > Scanners and Cameras both my scanner and
webcam are listed but with #4 and #3 next to them respectively.

They both seem to be working OK just wondered if it was anything to worry
about. I'm guessing that sometimes when disconnecting the info regarding
that device is not completely removed.

I have 4 USB ports on PC and a Belkin 4 port USB hub connected to one of
them which brings me to....

2. On occasion (why is it that these things only happen sometimes!?) it
seems as if my 4 port hub is working fine then all of a sudden, for no
apparent reason the hub, and devices plugged therein, become unrecognised by
the PC (I get the downward doorbell sound notification) and then shortly
afterwards become rediscovered (upward doorbell).

Is this a problem with the hub itself? Or the settings or driver for the hub
on the PC?

Any suggestions gratefully received.

Yours

RAH.

 

[Quaoar]

Hi,
2 possibly related questions here:
1. I am running Windows XP home and have had reason (due to other
issues) to disconnect and reconnect various USB devices from my PC.

When I look in Control Panel > Scanners and Cameras both my scanner
and webcam are listed but with #4 and #3 next to them respectively.

They both seem to be working OK just wondered if it was anything to
worry about. I'm guessing that sometimes when disconnecting the info
regarding that device is not completely removed.

I have 4 USB ports on PC and a Belkin 4 port USB hub connected to one
of them which brings me to....

2. On occasion (why is it that these things only happen sometimes!?)
it seems as if my 4 port hub is working fine then all of a sudden,
for no apparent reason the hub, and devices plugged therein, become
unrecognised by the PC (I get the downward doorbell sound
notification) and then shortly afterwards become rediscovered (upward
doorbell).

Is this a problem with the hub itself? Or the settings or driver for
the hub on the PC?

Any suggestions gratefully received.

Yours

RAH.

On all of my XP systems, there is one device entry for each USB
controller (one per USB port) that had the device connected. AFICS,
this is normal since each port is itself an independent device. The
problem with your disconnection is either too many devices on an
unpowered external hub, or a cable problem.

Q

 

[Opinicus]

2. On occasion (why is it that these things only happen
sometimes!?)
You're lucky. Sometimes I didn't even get the doorbell. It
seems to be a power supply problem. Are you using a UPS? If
so, you might want to consider beefing it up. I did and that
seems to have got rid of the problem of my USB drive "going
AWOL".

 

[Jeff Qiu [MSFT]]

Hi RAH,

For the first question, that #3 and #4 can be safely ignored.

Actually, the device drive is just like a new instance from a certain
class. The #3 and #4 means the 3rd and 4th time to create an instance from
a certain class. It can be reproduced to remove and reinstall the same
device drive.

For the second question, it is probably related to the power.

Each USB root hub can provide 500mA power.

If you connect it to several non-self-powered USB hubs, it may run out of
power.

You can check the power used from the power tab of the USB hub node from
the device manager.

Hope it helps!

Best Regards,

Jeff Qiu
Microsoft Online Partner Support
MCSE 2000, MCDBA, MCSA
Get Secure! - www.microsoft.com/security
This posting is provided "as is" with no warranties and confers no rights.

--------------------

 

[RAH]

Thanks for your response. I have tried using the hub both with its external
power supply and without. Same thing occurs. When I look under the power
properties of each device they all fall within the maximum 500 mA allowed
per port and therefore I would have thought that the external power supply
was not needed.

Could it be, in your opinion, anything to do with the USB controllers on the
PC itself? I've tried clearing the option under USB hub properties > power
management for the PC to "Allow he computer to turn off this device to save
power" but the same thing occurs.

If I could in some way log the time that each disconnect/reconnect event
occurs I might be able to trace the problem.
Then again I could just plug and unplug from ports on my PC as required and
do away with the hub altogether.

Hmmmmm....

RAH.

 

[Jeff Qiu [MSFT]]

Hi RAH,

As far as your other USB devices works on this hub, the problem should not
be related to the USB controller driver.

However, it is possible that this kind of USB hub hardware may have some
problems that randomly leads to the issue you experience.

If possible, please connect all devices (or the device that had experience
this issue) to the root USB hub (If there are enough port provided) on your
motherboard for a try.

Hope it helps!

Best Regards,

Jeff Qiu
Microsoft Online Partner Support
MCSE 2000, MCDBA, MCSA
Get Secure! - www.microsoft.com/security
This posting is provided "as is" with no warranties and confers no rights.

--------------------