COM port dead?

[Christina]

I have a client whose laptop appears to have a dead COM
port, although I'm wondering if it's a driver issue.
Basically a serial mouse connected is undetected, and
connecting the port via serial cable to the voice-mail
system also fails. No errors in Device Manager.

I tried the COM loopback test from B&B Electronics, which
failed. The RS-232 tester comes up red on TD. COM port
settings in Windows and BIOS match and are standard. No
conflicts from modem. Changed Boot POST to thorough. No
impact. Connected serial mouse as a test. Serial mouse
not detected. Event viewer shows errors for the i8042
chip. i8042 controls the keyboard and PS/2 mouse. Even
though this is the serial port, I'm assuming this error
is causing the COM port failure. Registry settings for
i8042 do not look unusual. KB article #257729 states
that keyboards/mice can become unresponsive when Natural
Keyboard Pro driver is installed. Steps on article
indicate that the driver on this laptop is incompatible,
although Windows Update does not list anything more
recent.

Any ideas?

 

[Jack Lee]

I had the same problem with a customer's computer I was fixing. To me
it sounds like the serial mouse is dead. You might want to try
replacing the serial mouse with a working one.

I found a place on the internet that actually sells this hard to find
serial mouse. http://www.hardwarecooling.com/product_info.php/cPath/92/products_id/443

I hope this helps.

 

[Christina Strack]

Hi Jack,

Thanks for your feedback. It's not the mouse because it has the same
problem connecting via serial cable to the voice-mail system. But thanks
for the handy link regardless.

 

[Thomas Lutz]

you might try deleting the COM port from the Windows Device Manager
and then rebooting the PC. When Windows starts back up it will
automatically find the serial port and reinstall the driver for it.
This will normally reset everything and in most cases it will revive a
dead COM port. It's not a guaranteed fix however it has worked for me
many times in the past.