Some of the morre widely used terms and what they mean.
- AUC – Authentication Centre – A network security device which checks that the customer can use the GSM System.
- BSC – Base Station Controller – Part of the network which electronically supervises a number of BTS’s
- BSS – Base Station System – A term meaning the combination of a BTS and a BSC on the same site.
- BTS – Base Transceiver Station – The aerial site within the cell which transmits and receives radio signals to and from the mobile phone.
- CSA – Called Subscriber Answer Signal – An inaudible signal which is transmitted to start the billing charges – usually on answer.
- EIR – Equipment Identity Register – The device which can be used to check the validity of the phone itself.
- GSM – Global System for Mobile Communications – The international standard for digital mobile phones.
- HLR – Home Location Register – A database of information in the MSC about mobiles using their own network (class of service, current location etc)
- IMEI – International Mobile Equipment Identity – The 15 digit serial number which identifies the GSM handset.
- IMSI – International Mobile Subscriber Identity – A special number which is initially used my the SIM card to identify itself to the network.
- Kc - Enryption Key – A scrambling process to prevent conversation being heard on the radio channels.
- Ki – Secret Key – An algorithm embedded within the SIM card which is used to validate the user.
- MSC – Mobile Switching Centre – The telephone exchange which links calls across the mobile phone network.
- MSISDN – Mobile Station International ISDN number – The telephone number which is dialled to contact the mobile user (eg 07802, 07900 etc).
- MSRN – Mobile Station Roaming Number – A number sent from a foreign network to the home network which allows calls to be forwarded to the roaming mobile.
- NMC – Network Management Centre – The control centre which monitors and supervises the entire network.
- OMC – Operations Management Centre – A computer system designed to look after a particular region of the network.
- PIN – Personal Identification Number – A number (4-8 digits long) which is used to protect a SIM card from misuse by others.
- PLMN – Public Land Mobile Network – A mobile phone network operator eg Vodafone, O2, T-Mobile etc
- PSTN – Public Switched Telephone Network – The land networks eg Virgin, BT etc
- PUK – Personal Unblocking Key – An 8 digit number used to reactivate a blocked SIM card of the wrong code has been used 3 times in succession.
- RANN – Recorded Announcement – A short voice message informing the user what has happened to the call attempt.
- SIM - Subscriber Identity Module – A smart card with a microprocessor which a user needs to use the GSM network.
- TMSI – Temporary Mobile Subscriber Identity – An ever changing series of numbers used by the network to contact the SIM card user.
- VLR – Visitor Location Register – A database of information i the MSC about visiting (roaming) mobiles from other networks (eg class of service, current location etc).
