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Table 2-19 solving usb, Problems – Compaq V300 User Manual

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2-38

Troubleshooting

COMPAQ CONFIDENTIAL - NEED TO KNOW REQUIRED

Writer: David Calvert Saved by: The Integrity Group Saved date: 10/26/00 11:45 AM

Part Number: 128679-006 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 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 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.