1. Ask questions - has anything changed? ("Oh, I was mopping behind the computer this morning ...") ("You know, there is a brown spot around that outlet like it caught on fire ...") 2. Restart lpsched with the -d option The debug option prints useful tracking information to the log files. 3. Modify the interface scripts. As an example, echo debug information from the script to a file in the "/tmp" directory. 4. Send some text to local devices with "cat" or another command. 5. Use hwconfig, stty, and other tools to debug serial communication problems.