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Troubleshooting 16-25
Writer: Lorise Fazio Saved by: J Abercrombie Saved date: 12/08/98 4:55 PM
Part Number: 310296-002 File name: Ch16.doc
Solving USB Problems
Problem Possible Cause Solution
External device
connected to a USB
connector does not
work
The operating system
limits external devices
connected by USB to
two tiers which can
include no more than
two hubs on the first
tier and no more than
one keyboard and
one pointing device
on the first or second
tier.
Reduce the number of
connected external USB
devices to no more than
two hubs on the first tier,
and no more than one
keyboard and one pointing
device on the first or
second tier.
External device
connected to USB
connector does not
work during startup
(before Windows 95
loads)
During startup, only
two tiers are
supported by the USB
connector. These
tiers can include no
more than two hubs
on the first tier and no
more than one
keyboard and one
pointing device on the
first or second tier.
Use the external device
only after Windows 95 has
loaded.
Reduce the number of
connected external USB
devices to no more than
two hubs on the first tier,
and no more than one
keyboard and one pointing
device on the first or
second tier.
External devices in
lower tiers do not
work
An unpowered hub is
connected to another
unpowered hub.
Use only powered hubs.
Make sure that all
unpowered hubs are
immediately preceded by
powered hubs in the USB
chain.
IMPORTANT: External USB keyboards will not function until the
operating system has been booted.