Compaq Prosignia 190 Maintenance And Service Manual page 127

External device
connected to a USB
connector does not
work.
External device
connected to USB
connector does not
work during startup
(before Windows 95
loads).
External devices in
lower tiers do 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.
During startup, only two
tiers are supported by the
USB port. 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.
An unpowered hub is
connected to another
unpowered hub.
Return to the top.
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.
Use the external device only
after Windows 95 or
Windows 98 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.
Use only powered hubs.
Make sure that all
unpowered hubs are
immediately preceded by
powered hubs in the USB
chain.