Siemens C56 - Manual (Page 19)

Security
18
ChangePhonecode
You define and enter the phone
code (4 - 8 digits) when calling up a
phone code protected function for
the first time. It is then valid for all
protected functions.
Clear SIM card barring
If the SIM card is barred, enter the
PUK (MASTER PIN) provided by your
service provider with the SIM card,
according to instructions. If the PUK
(MASTER PIN) has been lost, please
contact your service provider.
Note
Screensaver...................................... p. 64
Auto key lock..................................... p. 67
Further security settings.................... p. 75