Using the phone : Adjusting the telephone settings : Setting your country and local area codes
Setting your country and local area codes
Your area code (international and local area code) must be saved on the phone before you can transfer phone numbers (e.g. in vCards). Some of these numbers are already preset. Please ensure that the prefix is correctly separated from the rest of the area code.
*      OK    Telephony   OK     Area Codes   OK    Navigate to the entry field, delete the number using if needed   Enter the number   Save