Fixed Dialing Number

Fixed Dialing Number ( FDN ) or fixed dialing is a feature of the SIM card (Subscriber Identity Module) card of GSM phones.

Function

The phone numbers or ranges of numbers stored in the FDN list. If you activate the feature, then outgoing calls them, will be limited in the FDN list. Emergency numbers are not affected and can be selected. Not all SIM cards support this feature. To activate PIN2 is required. Thus changing the FDN list prevents unauthorized users. A useful application is, for example, limiting the numbers of a phone of children by the parents.