After attaching a Microsoft Intellimouse to a Swann USB Multihub the computer speakers stop functioning properly and emit a droning noise. However, the mouse and speakers work fine with the mouse connected to the PS/2 port (with adapter). A printer and joystick are connected via the hub with no problems. The computer is a Pentium 1.6 GHz running Windows Me.

My original thoughts were the computer may have run out of interrupt request (IRQ) locations. These are locations where the computer expects an interrupt to be generated when a device needs to signal the computer. Each device should have a unique IRQ assigned. Thus, when you plugged in the mouse an IRQ conflict may be caused between the mouse and the computer sound card (which has an IRQ assigned depending on the sound card’s position in the PCI computer’s internal PCI bus, also known as expansion slots). One point of interest was whether the USB hub itself took an IRQ, and then whether the devices connected to the USB hub also took up an IRQ. However, from the tests I have conducted using USB hubs, this does not seem to be the case. Only the USB host controllers have an assigned IRQ. Then, a USB hub (which has the USB ports) is connected to the controller and is not assigned an IRQ. So, the USB ports you see on the front and back of your computer are, essentially, a USB hub which is connected to the USB controller. You can then plug another USB hub into the USB ports on your computer, which gives the following relationship: USB Hub (your Swann USB Multihub) –> USB Hub (the ports on your computer) –> USB controller (inside your computer).

Returning to your specific problem, it is possible that the problem is related to a conflict of some description. Plug the mouse into the USB hub and go to the ‘Start’ menu > ‘Settings’ > ‘Control Panel’ and open the ‘System’ control panel. In the window that appears, click the ‘Device Manager’ tab. Locate your sound card in the list of devices then right-click on the device and select ‘Properties’. In the next window, click the ‘Resources’ tab. Note the IRQ address and check the conflict list for any entries. Close the window and find your mouse in the list of devices and repeat the same procedure. Compare the two IRQ addresses to see if they are the same. However, be aware that there may not be a ‘Resources’ tab in the mouse properties, in which case you cannot compare the IRQ of both devices. Please let me know the results of this procedure and I will try to work through the problem further with you.