Quicall

Java Card SIMs are based on the Java Card standard, which is a subcategory of  the Java programming language used for embedded systems. This allows the SIM card to contain programs which are hardware independent and interoperable.

The SIM cards store information to authenticate and identify users on the cellular network. This information includes:

1. IMSI  : International Mobile Subscriber Identity , which is unique for a subscriber on a particular network

2. ICC-ID : Integrated Circuit Card ID , which is used to identify the card internationally. This data is engraved on the SIM card as well as stored in it

3. Authentication Key (Ki) :  It is a 128 bit value assigned to the SIM card during the personalization process.  This Ki is also stored in the network carrier’s database , the home location register. It is used to authenticate the SIM card on the mobile network.

Other information stored on the SIM card include the Local Area Identity (LAI),  Operator Specific Emergency number, Short message service number, Service provider name.

A Subscriber Identity Module (SIM) card is a removable card used in all  GSM mobile phones.  Unique subscriber information (IMSI) is stored securely on the SIM card. The SIM card allows the subscriber to change mobile phones without changing the mobile phone number for a particular service provider, by inserting the SIM card in the new mobile phone. For CDMA phones, the Removable User Identity Module (RUIM) is the equivalent of  the SIM card, though RUIM cards are less widely sold.

Standard SIM cards are the size of  a credit card - 85.60 mm X 53.98 mm X 0.76 mm . Newer miniature SIM cards are smaller (25 mm X 15 mm) , though the thickness of the cards remains the same.

The cost of  a SIM  card  varies according to the data storage capacity of the card . Cheapest SIM cards have a capacity of 2-3 KB and SIM cards of capacity 16 to 32 KB are common in low cost mobile networks. High end SIM cards have a memory of  1 GB . SIM card capacity depends on the cellular service provider.