Dell Latitude CP, Справочное и ремонтное руководство

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3-26 Dell Latitude CP Reference and Troubleshooting Guide
Troubleshooting Serial and Parallel
Ports
This section provides a procedure for troubleshooting the
ports on your computer’s serial and parallel ports (shown
in Figure 3-3) and any attached peripheral devices. This
section also provides a procedure for troubleshooting the
computer’s infrared ports.
If a system error message indicates a port problem or if
equipment connected to a port seems to perform incor-
rectly or not at all, the source of the problem may be any
of the following:
•
A faulty connection between the I/O port and the
peripheral device
•
Incorrect settings for system setup options
•
Incorrect settings in the operating system’s
configuration files
•
A faulty cable between the I/O port and the
peripheral device
•
A faulty peripheral device
•
Faulty I/O port logic on the system board
•
Conflicting COM port settings
•
Lack of device drivers
Troubleshooting the Basic I/O Functions
Make a copy of the Diagnostics Checklist found in Chap-
ter 5, and fill it out as you complete the following
procedure.
1. Check the settings for the Serial Port and Parallel
Mode setup options.
For information on configuring the ports, see
Chapter 2, “Customizing System Features.” Are the
communication port options set correctly for the
peripheral devices connected to the computer?
Yes. Go to step 3.
No. Continue to step 2.
2. Change the Serial Port and Parallel Mode options
to the appropriate settings; then reboot the system.
Is the problem resolved?
Yes. You have fixed the problem.
No. Continue to step 3.
3. Check the contents of the initialization and
start-up files. (See “Installing and Configuring
Software” found earlier in this chapter.)
Are the port configuration commands correct?
Yes. Go to step 5.
No. Continue to step 4.
4. Change the necessary statements in the start-up
files.
If the port problem is confined to a particular appli-
cation program, see the application program’s
documentation for specific port configuration
requirements.
Is the problem resolved?
Yes. You have fixed the problem.
No. Continue to step 5.
5. Insert the Dell Diagnostics Diskette into drive A,
reboot the computer, and run the Serial/Infrared
Ports test group and/or the Parallel Ports test group.
(See Chapter 4, “Running the Dell Diagnostics.”)
The Serial/Infrared Ports test group and the Parallel
Ports test group check the basic functions of the system
board’s I/O port logic. Also, if a parallel printer is con-
nected to the parallel port, the Parallel Ports test group
tests the communication link between the system
board’s I/O port logic and the printer.
Do the tests complete successfully?
Yes. The problem may be with the external device.
Check the documentation that came with the device
for any troubleshooting procedures.
No. Call Dell for technical assistance. See Chap-
ter 5, “Getting Help,” for instructions.
6. The problem may be with the external device.