Remote lock
You can lock your device from another device using a text
message. To enable your device to be locked remotely, and
to define the lock message to be used, select
>
Settings > Settings > General > Security and Phone and
SIM card > Remote phone locking. When you have entered
the message, select OK. The message can be up to 20
characters long.
To lock your device, send the lock message as a text message
to your mobile phone number. To unlock your device later,
select Unlock, and enter the lock code.