Home Location Register

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The Home Location Register (HLR) is where the netwrok stores the subscription data. It stores the permanent data about subscribers including their profile, what services they can use, their location. This data is based on the SIM number, the number of the SIM allocated to that customer.

The Subscriber Identity Module (SIM) is the small card inserted into a MS to give the user access to the network. Each SIm has a unique number, IMSI. This is made up of 3 components. The Mobile Country Code (MCC), Mobile Network Code (MNC) and a unique number.

For the UK these are the codes :

BT234-76 or 234-77
EE (Orange)234-33 or 234-34
Three234-20 or 234-94
O2234-02 or 234-10 or 234-11
EE (T-Mobile)234-30 or 234-31 or 234-32
Vodafone234-15 or 234-27 or 234-91

In addition each SIM will have a home number stored in the HLR. This is the Mobile Subscriber ISDN (MSISDN) which in the UK will be of 11 digits starting with 07.