What it Means & What to Do

9 times out of 10 this means that there is something wrong with their phone line, but there are a few things you can do to the terminal to make sure.

Verify if there is a PABX number. (dial 9 to get out?) 

Changing the PABX Code

Not that? Is the Baud Rate too low? 

Changing the Baud Rate 

Had enough? One more thing you can do is try turning on Blind DIal.

Turning on Blind Dial

If all of the above is unsuccessful, send DSL filter and explore IP possibilities.