Samsung IP-830w Owner's Manual page 168

Note: The SIM PhoneBook provides three default fields ( Name ,
Phone Number , and Index ). This information is stored on your
SIM card to provide information mobility. When PhoneBook
entries are moved or copied to Contacts, all input fields are
available for entry; however this information is not stored on
the SIM card.
160 Section 2I: Sprint Worldwide Wireless Service