Dell PowerEdge 6350 Installation And Troubleshooting Manual page 71

The four subtests in the Serial/Infrared Ports Test group and the port functions they
test follow:
Serial/Infrared Baud Rate Test
Checks the baud rate generator in each serial communications chip against the
computer's clock
Serial/Infrared Interrupt Test
Checks the serial port's ability to send IRQs to the microprocessor
Serial/Infrared Internal Transmission Test
Checks several internal functions of the serial port using the internal loopback
mode of the serial communications chip
Serial External Transmission Test
If a loopback device is attached, checks the line control bits of the serial port and
sends a test pattern at several baud rates, checking the returned values
If the diagnostics does not recognize the computer's serial or infrared ports, enter the
System Setup program and check the Serial/Infrared Port option to see whether the
port has been disabled. (See Chapter 4, "Using the System Setup Program," in the
system User's Guide for instructions.) The subtests in the Serial/Infrared Ports Test
group cannot test a port unless it is enabled.
When a port is faulty, it may not be immediately evident that the port, and not the
device connected to the port, is faulty. Instead, the peripheral might behave erratically
or not operate at all. If the external device is not properly installed through the
software, it also may not function properly. Try operating the peripheral from different
programs or through the operating system. If it still does not work, you can eliminate
the software configuration as the cause of the problem.
Another possible cause for errors is the external device. Use the documentation that
came with the peripheral to troubleshoot the device and confirm that it is working
properly.
After you eliminate incorrect system configuration information settings, peripheral
malfunctions, and software errors as potential causes of port problems, you can run
the subtests in the Serial/Infrared Ports Test group to check the hardware. Although
the following symptoms can be caused by faulty peripherals or software errors, they
might also suggest a port problem:
If a peripheral works intermittently or produces intermittent errors, the port may
be faulty.
If the computer displays an error message that is related to the external device
connected to a port but corrections to the device do not resolve the error, run the
appropriate subtest in the Serial/Infrared Ports Test group.
Running the Dell Diagnostics 5-21