Fixed Dialing Number (FDN) is a service mode of a GSM

mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive telephone call, calls over a radio freq ...

SIM card A typical SIM card (mini-SIM with micro-SIM cutout) A file:Simkarte NFC SecureElement.jpg">thumb"> thumb">A TracFone Wireless SIM card has no distinctive carrier markings and is only marked as a "SIM card" A SIM card (full form Subscriber Ide ...

. Numbers are added to the FDN list, and when activated, FDN restricts outgoing calls to only those numbers listed, or to numbers with certain prefixes. A notable exception is that emergency calls to 000, 112, 911, 999 and the like are exempt. Incoming calls are not blocked by FDN. One practical application of FDN is for

parent A parent is a caregiver of the offspring in their own species. In humans, a parent is the caretaker of a child (where "child" refers to offspring, not necessarily age). A ''biological parent'' is a person whose gamete resulted in a child, a male ...

s to restrict the phone numbers their children can dial. The SIM card's PIN2 must be entered beforehand or when applying such settings.

References

{{Wireless-stub GSM standard