120Glossary of TermsPIN Personal Identification Number used for SIM cardsecurity. Supplied by your service provider. If the PIN orPIN2 is entered incorrectly several times (three times forPIN2), the PIN or PIN2 will be blocked.PIN2PLMN Public Land Mobile Network. A network that provides landmobile telecommunications services.PUK PIN or PIN2 Unblocking Key. Used to unblock the PIN orPIN2 code. Supplied by your service provider. If the PUKor PUK2 is entered incorrectly 10 times, your SIM cardwill be blocked permanently. All information stored in theSIM card will be lost and the SIM card will need to bereplaced.PUK2Roaming The ability to use your phone on networks other than yourhome network.SDNService Dialling Number. This number enables you toaccess special services provided by your networkoperator, such as customer support, emergency services,etc.ServiceproviderThe organisation responsible for providingsupplementary services and applications to phones.SIMSubscriber Identity Module. A small smart-card whichstores unique subscriber and user-entered informationsuch as Contacts entries and SMS messages. Suppliedby your service provider.STK SIM Tool Kit. Supplied by your service provider. It isincluded in the SIM card to offer value-added services.WAPWireless Application Protocol. The communicationstandard which enables you to download resources fromthe Internet to your phone.
