You can download additional ringtones from the iPECS server.  Downloaded ringtones replace whatever ringtones are currently stored in ringtone numbers 5, 6, 7 and 8. on your phone.

See Modify Ringtone for steps to  select a new ringtone for internal and/or external calls.

Download and replace ringtones 5 - 8

1. Press the Menu button.
2. Press 2  (Ring).
3. Press 3  (Ring Download).
4. Press 5, 6, 7, or 8 to view the ringtones that are available for download. Use the Up and Down directional buttons to scroll through the list.
5. To listen to a selected ringtone, press its number or press Select.
6. Press 1 (Yes) to register the ringtone for use on your phone, or 2 (No) to discard it.
7. Press Back to return to the previous screen. Press Exit to exit Menu.