Retreiving messages from another phone (by 4 users)

The default code 123 did not work for me.

Call your telephone No.
After you hear beep that follows your greeting enter your 3 digit security code. to bypass the greeting enter your 3 digit code any time while the greeting is playing
Unit beeps to confirm you have accessed the remote functions and begins playing the remote functions menu
Select the function you want to use and press that number on the phones keypad that you are using
To end the call hang up or press the "6" button while the menu is playing.

Also, it should be noted that if you're reading tajen's excellent answer and saying to yourself: "3 digit code...???"

If you've never programmed one your default code is 123.