Troubleshooting 2-35
Solving USB Problems
Table 2-26
Solving USB Problems
Problem Probable Cause Recommended Action(s)
External device connected to
a USB connector does
not work.
The operating system limits
external devices connected
by USB to two tiers that 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 a
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.