dongle issues

[samsc]

Hi,
I'm running m119 on a mac pro and have a regular ittermitant fault where catalyst fails to see the dongle. I've had this happen on occassion with a few other identical servers (I have six indentical systems) but not by any meens with the same regularity. Also sometimes it will be fine straight after booting catalyst but then loose the dongle about an hour later.
I'm guessing it is a hardware fault with the USB on the Mac, could anyone reccomend what to do from here to confirm this?
I've currently swapped the dongles with another machine to see if the fault moves or not, and so far the fault hasn't re occured.

All suggestions welcomed.

you have a usb card with your dongle?

[kiwi]

Hi all thanks for your replys,
Yes the dongle is straight into the Mac as I dont have a spare PCI slot (two LFG cards)
Richard thanks for the tip about file sharing, it is on at the moment I will try turning that off, although it is turned on on the back up server and that is working fine.
I ment to mention in the orginal thread that catalyst sometimes loses the USB keyspan serial adaptor in the custom serial output box when it doesnt see the dongle. The TCP ones are fine -this is what makes me think it is a hardware fault.
Is there diagnostic tool for the USB bus?