181Glossary of TermsNetworkOperatorThe organisation responsible for operating a GSMnetwork.Password Used for the control of Call bar. Supplied by your serviceprovider.PIN / PIN2 Personal Identification Number used for SIM cardsecurity. Supplied by your service provider. If the PIN orPIN2 is entered incorrectly several times (3 times forPIN2), the PIN or PIN2 will be blocked.PUK / PUK2 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, the PUK orPUK2 will be blocked.Roaming The ability to use your phone on networks other thanyour home network.Service provider The organisation responsible for providing access to theGSM/GPRS network.TLS Transport Layer Security. A network layer that looks afterthe security of the communication session.UDP User Datagram Protocol. A communications protocol,which makes it possible to send a datagramtransmissions from one device to a recipient device.USSD Unstructured Supplementary Services Data. Similar toSMS, USSD uses the GSM network's signaling path totransmit information. Yet, USSD is session-oriented.WAP Wireless Application Protocol. The communicationstandard which enables you to download resources fromthe Internet to your phone.XHTML eXtensible HyperText Markup Language. Works as anapplication of XML. Whereas HTML only describes howthe data should be displayed or used, XML describes thetype of data.
