Samsung SCH-S720C User Manual page 16

Locking the phone
By default, the phone locks automatically when the screen
times out.
– or –
Lock the phone by pressing the
Unlocking the phone
Unlock the phone using one of the default unlock screens, or for
increased security, use a personal screen lock PIN, password, or
pattern.
Press the Power/Lock Key, then touch and drag your
finger in any direction across the screen to unlock.
12
Power/Lock Key.