Samsung Galaxy S II

Find "Voice call"

Press Applications.

Find "Voice call"

Press Settings.

Find "Voice call"

Press Call.

Find "Voice call"

Press Additional settings.

Find "Voice call"

Press Call barring.

Find "Voice call"

Press Voice call.

Select barring option

Press one of the following options:
All outgoing calls

Select barring option

Int'l calls

Select barring option

Int'l calls except home

Select barring option

All incoming calls

Select barring option

Incoming when roaming

Select setting

Key in your barring password (default is 0000).
Press OK.
The request is sent.
The action is confirmed on the display.

Exit

Press the Home key to return to standby mode.