USB bandwidth problems

  • Thread starter Thread starter -keevill-
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-keevill-

I am running into difficulties with USB bandwidth on my PC. I have got a
USB keyboard and mouse, USB microphone and I am also using a USB port for
the connection of my pocket PC. If I now plug-in my web cam, I get errors
saying that the bandwidth is insufficient. Is there anything which I can do
to increase the bandwidth? Or is this dependent upon the motherboard? I
have already purchased a powered hub but this does not help. I always
believed that you could simply daisychain a large number of USB devices but
it appears not.
 
The transfer rate on anything is limited and when you reach that limit
then you can't add any more devices. With USB 1.1 it is limited to 12
mb. You can attach multiple low speed devices like keyboard and mouse
but only 1 high speed devices like microphone or web cam. You have to
use another port for additional devices. Your system should have at
least 1 more port and many systems will have a total of 4 or even 8
ports. Also if you system is newer it will have some USB 2 ports which
are 480 mb speed.

Leonard Severt

Windows Setup
 
The transfer rate on anything is limited and when you reach that limit
then you can't add any more devices. With USB 1.1 it is limited to 12
mb. You can attach multiple low speed devices like keyboard and mouse
but only 1 high speed devices like microphone or web cam. You have to
use another port for additional devices. Your system should have at
least 1 more port and many systems will have a total of 4 or even 8
ports. Also if you system is newer it will have some USB 2 ports which
are 480 mb speed.
Click to expand...
I have 2 USB ports at the rear and 2 at the front. It doesn't matter whether
I attach the cameras into the front port and rear port (one in the front one
in the back) I still get the error bandwidth exceeded message. I have tried
this on another machine which has no other USB devices and the same thing
happens. These two cameras are small and even setting the image size down
to minimum I cannot get both of them to operate. Certainly, they are
nowhere near the 12MB limitation that you speak about. Is there some
setting in the BIOS or even within Windows 2000 itself which is needed to
increase the bandwidth? Thanks for your help.
 
-keevill- said:
I have 2 USB ports at the rear and 2 at the front. It doesn't matter whether
I attach the cameras into the front port and rear port (one in the front one
in the back) I still get the error bandwidth exceeded message. I have tried
this on another machine which has no other USB devices and the same thing
happens. These two cameras are small and even setting the image size down
to minimum I cannot get both of them to operate. Certainly, they are
nowhere near the 12MB limitation that you speak about. Is there some
setting in the BIOS or even within Windows 2000 itself which is needed to
increase the bandwidth? Thanks for your help.
Click to expand...

under hardware in the device manager of control panel
deselect "disable USB error detection" and see if this makes
a difference

Geoff
 
under hardware in the device manager of control panel
deselect "disable USB error detection" and see if this makes
a difference

Geoff
Click to expand...
Thx Geoff, good suggestion but all that does is to disable the error message
but the second camera shows blank and the program suggests that the camera
is in use with something else. By the way, for testing purposes, I have set
the cameras are on a new machine with no other USB devices present apart
from the two small WebCams. It is a reasonably new machine with four USB
ports, two at the back and two at the front. They appear to be on separate
USB controllers so I am rather stumped why I can only run one USB camera.
 
I've just found this on the Net
a.. Two identical webcams might appear as one to the system, because you
only can install one driver. This might not be the case for all brands, but
beware of the problem before you go out and spend a fortune on identical
webcams.
It might appear that the USB controllers see them as 1 camera ?? Any
suggestions from anyone how to 'trick' the system if this is indeed the
case?
 
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