#TN028

 #Summary

I get an error message which says' Serial Port COM1 General Fault' or Com Port already in Use' .
or similar message

 #Problem  
Another program or system device is already using the serial port

#Solution  

Check to see if another program is using the serial port, also note some programs might
run in the background or schedule themselves to run. Typical of this are mobile phone
applications that detect when a mobile phone is plugged into the serial port.
If you have an Internet connection check that Outlook or other programs do not 
periodically try to go on line

If any of the above is true - You have two options

1. Disable or uninstall the other program using the serial port.

2. Install an additional serial com port - See tech Note #TN025

Otherwise there is probably a problem with the serial port.

Check that the serial port actual exists (#TN025) and is operating correctly
(Infra red is often assigned to com port 1)

Refer to your PC reference manual on how to diagnose fit a replacement part.

Note: Using a USB serial adaptor is often the easiest and cheapest way of  solving a
repair problem.