A
subscriber identity module (SIM) is a
smart card
inside of a
GSM
cellular phone that
encrypts voice and data transmissions and stores data about the specific user so
that the user can be
identified and
authenticated to the network supplying the phone service. The SIM also
stores data such as personal phone settings specific to the user and phone
numbers. A SIM can be moved from one phone to another and/or different SIMs can
be inserted into any GSM phone. For example, if a user has one phone but uses it
for both personal and business calls, he can change the SIM depending on how he
will be using the phone (one card contains his personal identity and data and
the second card carries his business identity and data).
A SIM also is referred to as a SIM card.
