Most smartphones support this through their "Supplementary Services" or "Call Settings" menus. Activating or deactivating the service usually requires a provided by your carrier; common default codes include 0000 or 1234 .
Prevent unauthorized use of a device by staff or children, or block unwanted disturbances during specific times. call barring meaning
Call Barring is a telephony service feature that allows the user to prevent specific types of incoming or outgoing calls from being connected. Unlike "blocking a number" (which rejects a specific person), Call Barring typically blocks categories of calls (e.g., all international calls, all premium-rate numbers, or all incoming calls while roaming). all international calls
