To disable a phone number, go to the phone number address and enter [Reset/*] followed by [5] (Hex F). Next set the communication formats for both phone lines to disabled.
1) Enter programming by pressing the installer code (default 98765) followed by #, 0
2) Enter 71, [Reset/*], 5 + # to disable phone number 1
Enter 72, [Reset/*], 5 + # to disable phone number 2
3) Enter 75, 000000 + # to disable communication format for Line 1
4) Enter 76, 000000 + # to disable communication format for Line 2
