Samsung SEC-R311ZGAUSC - Manual (Page 20)

17
Lock Mode
When the phone is in Lock Mode, restrictions are placed on
phone use. You can receive calls and messages, but cannot place
outgoing calls (except for emergency numbers) until you unlock
the phone. Lock Mode also restricts access to menus and the
Volume key. Unlock your phone by entering the lock code when
prompted. (For more information, refer to “Change Lock” on
page 109.)