If your modem still isn't found after trying one of the two(2) methods in the last section, you can use the dip dial-up program.   You can use dip interactively; that is dip allows you to enter a command and immediately see the result --- a great advantage when experimenting or troubleshooting modems.

dip -t 

   type the above command at the terminal prompt (log on as root) and hit the Enter key.   the dip> prompt appears

enter the following commands 

   DIP>port ttyS0

   DIP>dial 735-68-44

   If the modem picks up and dials, you've won the game.   

   If the modem doesn't pick up, then dip returns you to the command promt, and you should try the last step

If your Modem is Found 

   press the Enter key to immediatly kill the connection.   You are done !

Quit dip 

   you need to Quit dip and then restart the program so that you can try ports ttyS1, ttyS2, ttyS3.   

   Just modify the first command in the 1st step above to match the serial port you're targeting