(Note: Actual codes vary by carrier; modern smartphones have a UI for this in Settings > Mobile Network > Call Barring.) Call barring is a valuable, carrier-enforced tool for selectively restricting voice calls based on direction and destination. It differs from device-level blocking by working at the network core, making it reliable even if the phone’s software is tampered with. While its use has declined slightly with the rise of VoIP and data-centric communication, it remains essential for roaming cost management, corporate phone policies, and parental controls. Report prepared for general informational use. Actual feature availability and codes depend on your mobile network operator.