What is SIM?
SIM is a shortened form of subscriber identity module, also known as subscriber identification module. It consists of an integrated circuit card identifier which is used for the identification of specific network provider. It contains specific data which include phone number, network authorization information, personal security keys, user identity, location, contact list and limited messages. SIM cards, available in micro, standard and mini sizes, are used in two types of phones, including GSM phones and CDMA phones. Sim cards are portable and can be used in different mobile devices.