Glossary154provider with the SIM card. It may be a four to eight-digit number and can be changed, as required.PUK (PIN Unblocking Key)Security code used to unlock the phone when anincorrect PIN has been entered three times insuccession. The eight-digit number is supplied by theservice provider with the SIM card.RoamingUse of your phone when you are outside your homearea (when travelling for example).SDN (Service Dialing Numbers)Telephone numbers supplied by your networkprovider and giving access to special services, suchas voice mail, directory inquiries, customer supportand emergency services.SIM (Subscriber Identification Module)Card containing a chip with all the informationrequired to operate the phone (network andmemory information, as well as the subscriber’spersonal data). The SIM card fits into a small slot onthe back of the phone and is protected by thebattery.SMS (Short Message Service)Network service sending and receiving messages toand from another subscriber without having to speakto the correspondent. The message created orreceived can be displayed, received, edited or sent.
