Currently the fanvil_phonebook.xml is built containing only one number field from 3CX. Both the phone and 3CX support three number fields. Please include all three fields in export. If the resulting DirectoryEntry doesn't contain at least one number, then don't include that DirectoryEntry in the export. This avoids filling up the limited space in the Fanvil address book with entries that can't be dialled from the phone. 3CX - see ticket #159764 for more details.