955. GlossaryTo help you understand the main technical terms and abbreviationsused in this booklet and take full advantage of the features of yourmobile phone, here are a few definitions.Call BarringAbility to restrict outgoing and incoming calls.Call DivertingAbility to reroute calls to another number.Call HoldingAbility to put one call on standby while answering or making anothercall; you can then switch between the two calls, as required.Call WaitingAbility to inform users that they have an incoming call while engagedon another call.CLI (Caller Line Identification) ServicesServices allowing subscribers to view or block the telephone numbersof callers.EMS (Enhanced Message Service)Network service sending and receiving messages that include images,sounds and animations to and from another user without having tospeak to the correspondent.GPRS (General Packet Radio Service)New non-voice value-added service that allows information to be sentand received across a mobile telephone network. GPRS can providea continuous connection to the Internet for mobile phone andcomputer users, where network coverage allows. It is based on theGlobal System for Mobile Communication (GSM) circuit-switchedmobile phone connections and the Short Message Service (SMS).GSM (Global System for Mobile Communication)International standard for mobile phone communication, guaranteeingcompatibility between the various network operators. GSM coversmost European countries and many other parts of the world.Multiparty CallingAbility to establish a conference call involving up to five additionalparties.PIN (Personal Identification Number)Security code that protects the phone/SIM against unauthorised use.The PIN is supplied by the service provider with the SIM card. It maybe a four to eight-digit number and can be changed, as required.PUK (PIN Unblocking Key)Security code used to unlock the phone when an incorrect PIN hasbeen entered three times in succession. The eight-digit number is