Call barring is a mobile phone feature that allows the user to set certain prohibitions on incoming or outgoing calls. This is an effective means to prevent the phone being used to make expensive international or premium rate calls, particularly when the phone is to be used by people other than the subscriber.
Many companies that provide handsets for business use now employ call barring as a security measure, to control their use and restrict calls to pre-approved numbers. The user's personal code must be used to activate this feature.