Panasonic EB-A100 - Manual (Page 73)

70 Phone Menu
Codes
Change phonecode:
The Phonecode is used for the SIM lock, which protects the
phone from being used with a SIM other than yours.
From Phone Menu
1.
4 Security > Codes A (Select)
2. 4 Change phonecode A (Select)
3. Enter a new phonecode A (OK)
4. Enter the new phonecode to verify A (OK)
PIN control:
The PIN protects your SIM against unauthorised use. If you
enable the PIN, every time the phone is switched on you will
be prompted to enter the PIN.
From Phone Menu
1.
4 Security > Codes A (Select)
2. 4 PIN Control
3. Enter PIN number A (OK)
4. 4 Set to either enable or disable the PIN @ (Set).
5. A (OK)
NOTE: Your phonecode must be 4 to 8 digits. You are advised to write
down your phonecode. If the phonecode is entered incorrectly 3 times,
the phone will cease to operate permanently. If you change the
phonecode from the second time on, you must enter the previous
phonecode first, then enter the new phonecode twice.