905. GlossaryTo help you understand the main technical terms and abbreviations used inthis booklet and take full advantage of the features of your mobile phone,here are a few definitions.Call BarringAbility to restrict outgoing and incoming calls.Call ForwardingAbility to re-route calls to another number.Call HoldingAbility to put one call on Standby while answering or making another call;you can then switch between the two calls, as required.Call WaitingAbility to inform users that they have an incoming call while engaged onanother call.CLI (Caller Line Identification) ServicesServices allowing subscribers to view or block the telephone numbers ofcallers.GPRS (General Packet Radio Service)New non-voice value-added service that allows information to be sent andreceived across a mobile telephone network. GPRS guarantees acontinuous connection to the Internet for mobile phone and computer users.It is based on the Global System for Mobile Communication (GSM) circuit-switched mobile phone connections and Short Message Service (SMS).GSM (Global System for Mobile Communication)International standard for mobile phone communication, guaranteeingcompatibility between the various network operators. GSM covers mostEuropean countries and many other parts of the world.MMS(Multimedia Message Service)Network service sending and receiving messages to and from anothersubscriber without having to speak to the correspondent. The Messagesupports presentation of various media types, such as full color images andpolyphonic ringtones.Multiparty CallingAbility to establish a conference call involving up to five additional parties.PIN (Personal Identification Number)Security code that protects the phone/SIM against unauthorized use. ThePIN is supplied by the service provider with the SIM card. It may be a fourto eight-digit number and can be changed, as required.PUK (PIN Unblocking Key)Security code used to unlock the phone when an incorrect PIN has been