Solving USB Problems

Problem

Possible Cause

Solution

External device

The operating system

Reduce the number of

connected to a

limits external devices

connected external USB

USB connector

connected by USB to two

devices to no more than

does not work.

tiers which can include

two hubs on the first tier,

 

no more than two hubs

and no more than one

 

on the first tier and no

keyboard and one

 

more than one keyboard

pointing device on the

 

and one pointing device

first or second tier.

 

on the first or second tier.

 

External device

During startup, only two

Use the external device

connected to

tiers are supported by the

only after Windows 95,

USB connector

USB port. These tiers can

Windows 98, or

does not work

include no more than two

Windows 2000

during startup

hubs on the first tier and

Professional has loaded.

(before

no more than one

Reduce the number of

Windows 95,

keyboard and one

connected external USB

Windows 98, or

pointing device on the

devices to no more than

Windows 2000

first or second tier.

two hubs on the first tier,

Professional

 

 

and no more than one

loads).

 

 

keyboard and one

 

 

 

 

pointing device on the

 

 

first or second tier.

External devices

An unpowered hub is

Use only powered hubs.

in lower tiers do

connected to another

Make sure that all

not work.

unpowered hub.

unpowered hubs are

 

 

immediately preceded by

 

 

powered hubs in the USB

 

 

chain.

5-20Troubleshooting

COMPAQ CONFIDENTIAL - NEED TO KNOW REQUIRED

Writer: Karen Williams Saved by: Karen Williams Saved date: 05/23/00 11:51 AM

Part Number: 168894-001 File name: cH05.doc