Specifications

2-38 Troubleshooting
COMPAQ CONFIDENTIAL - NEED TO KNOW REQUIRED
Writer: David Calvert Saved by: JAbercrombie Saved date: 07/06/00 3:56 PM
Part Number: 128679-004 File name: Ch02
Table 2-19
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 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.
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.
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.