Fixed Dialing Number (FDN) is a feature of a phone's SIM card that can restrict outgoing calls only to a special list of numbers, or to numbers that match a certain template (like 0793519xx or 069xxx906). Incoming and emergency calls are not affected by this option, so 911 and 112 are always reachable.
As a parent, you can control the phone numbers your children can dial. For example, you can configure the SIM such that the kid can call only you, your spouse and your other child.
A business can use FDN as a security measure to prevent employees from dialing numbers outside the company from their corporate-paid account.
Fixed dialing is activated by entering PIN2. This prevents others from changing or disabling the FDN list. This number is usually distributed with the card itself. If you can’t find it, contact the mobile operator.
You can enable FDN on your phone, but editing the list of fixed dialing numbers can be cumbersome if you use the phone’s tiny keypad.
SIM reader with SIM Manager can enable FDN and edit the fixed dialing numbers much faster and easier.
The first thing you have to do is add the numbers you want to be able to dial. You can write them from scratch or copy them from your contacts.
Click Enable FDN feature in the option SIM menu:
- Enter PIN2.
FDN is now enabled on your SIM card. No outgoing calls can be made to any numbers, other than those in the list of fixed dialing numbers, or emergency numbers. Even if the SIM card is plugged into a different phone - calls to numbers other than the allowed ones are not possible.
Things to keep in mind:
- If you enter an incorrect PIN2 three times in a row, it will be locked. You can unblock PIN2 if you know PUK2. If you’re not sure what these numbers are, contact your mobile operator.
- Even though not all SIM cards support FDN, practically any SIM card issued these days has it. If your card does not, see if your mobile operator can replace it.