Oppo
Set Up Fixed Dialing Numbers (FDN) auf Oppo
Fixed Dialing Numbers (FDN) restricts outgoing calls and texts on your Oppo phone to a fixed list of approved numbers. Incoming calls and messages are not affected by this restriction.
The function is tied to your SIM card, not the phone itself. Activation requires PIN2, a second security code from your carrier that is separate from the regular SIM PIN. If you do not have PIN2, contact your mobile carrier before starting.
On ColorOS you manage FDN through the carrier call settings rather than a standalone app. Open Tap on Phone ➔ Open the Menu ➔ Tap on Settings ➔ Tap on Calling accounts ➔ Tap on Carrier call settings ➔ Tap on Fixed dialing numbers. On a dual SIM device, pick the SIM card you want to restrict first.
Tap Tap on Enable FDN and follow the instructions on screen, then enter PIN2 when prompted. Once enabled, you can build the list of allowed numbers from the same menu.
If outgoing calls fail right after enabling FDN, the number you dialed is likely missing from the allowed list. Emergency numbers stay reachable regardless of the FDN list.