Motorola C975 3G - Manual (Page 51)

Learning to Use Your Phone - 51
If your service provider has not reset these codes, we recommend
that you change them to prevent others from accessing your
personal information. The unlock code must contain 4 digits, and
the security code must contain 6 digits.
You can also reset your SIM card PIN code or PIN2 code, if
necessary.
To change a code or password:
Locking and Unlocking Your Phone
You can lock your phone manually or set the phone to lock
automatically whenever you turn it off.
To use a locked phone, you must enter the unlock code. A locked
phone still rings or vibrates for incoming calls or messages, but you
must unlock it to answer.
You can make emergency calls on your phone even when it is
locked (see page 61).
Locking Your Phone Manually
Find the Feature
M
>
Settings
>
Security
>
New Passwords
Find the Feature
M
>
Settings
>
Security
>
Phone Lock
>
Lock Now
Press To
1 keypad keys enter your unlock code
2 OK key lock the phone